document_title: History of silk

question_text: when did silk begin to be produced in china

text: History of silk

text: Early history[edit]

text: The Appearance of Silk[edit]

text: The earliest evidence of silk was found at the sites of Yangshao culture in Xia County, Shanxi, where a silk cocoon was found cut in half by a sharp knife, dating back to between 4000 and 3000 BC. The species was identified as Bombyx mori, the domesticated silkworm. Fragments of primitive loom can also be seen from the sites of Hemmed culture in Yuyao, Zhejiang, dated to about 4000 BC. The earliest example of silk fabric is from 3630 BC, and was used as wrapping for the body of a child. The fabric comes from a Yangshao site in Qingtaicun at Rongyang, Henan.[1] Scraps of silk were found in a Liangzhu culture site at Qianshanyang in Huzhou, Zhejiang, dating back to 2700 BC.[2][3] Other fragments have been recovered from royal tombs in the Shang Dynasty (c. 1600 – c. 1046 BCE).[4]

text: During the later epoch, the Chinese lost their secret to the Koreans, the Japanese, and, later, the Indians, as these cultures discovered how to make silk. Allusions to the fabric in the Old Testament show that it was known in western Asia in biblical times.[5] Scholars believe that starting in the 2nd century BCE the Chinese established a commercial network aimed at exporting silk to the West.[5] Silk was used, for example, by the Persian court and its king, Darius III, when Alexander the Great conquered the empire.[5] Even though silk spread rapidly across Eurasia, with the possible exception of Japan its production remained exclusively Chinese for three millennia.

text: Myths and legends[edit]

text: The writings of Confucius and Chinese tradition recount that, in about 3000 century BCE, a silk worm's cocoon fell into the tea cup of the empress Leizu.[6] Wishing to extract it from her drink, the 14-year-old girl began to unroll the thread of the cocoon.

text: She then had the idea to weave some of it, so she kept some for herself. Having observed the life of the silk worm on the recommendation of her husband, the Yellow Emperor, she began to instruct her entourage in the art of raising silk worms, sericulture. From this point, the girl became the goddess of silk in Chinese mythology. Silk eventually left China via the heir of a princess who was promised to a prince of Khotan. This probably occurred in the early 1st century AD.[7] The princess, refusing to go without the fabric that she loved, would finally break the imperial ban on silk-worm exportation.

text: Though silk was exported to foreign countries in great amounts, sericulture remained a secret that the Chinese carefully guarded. Consequently, other peoples invented wildly varying accounts of the source of the incredible fabric.

text: In classical antiquity, most Romans, great admirers of the cloth, were convinced that the Chinese took the fabric from tree leaves.[8] This belief was affirmed by Seneca the Elder in his Phaedra and by Virgil in his Georgics. Notably, Pliny the Elder knew better. Speaking of the bombyx or silk moth, he wrote in his Natural History "They weave webs, like spiders, that become a luxurious clothing material for women, called silk."[9]

text: Silk usage in Ancient and Medieval China[edit]

text: In China, silk-worm farming was originally restricted to women, and many women were employed in the silk-making industry. Even though some saw the development of a luxury product as useless, silk provoked such a craze among high society that the rules in the Li Ji were used to limit its use to the members of the imperial family.[4] For approximately a millennium, the right to wear silk was reserved for the emperor and the highest dignitaries. Silk was, at the time, a sign of great wealth, because of its shimmering appearance. This appearance was due to silk's prism-like shape/structure, which refracted light from every angle. After some time, silk gradually extended to other classes of Chinese society, like the noble class and such. Silk began to be used for decorative means and also in less luxurious ways: musical instruments, fishing, and bow making. Peasants did not have the right to wear silk until the Qing dynasty (1644–1911).[4]

text: Paper was one of the greatest discoveries of ancient China. Beginning in the 3rd century BC paper was made in all sizes with various materials.[10] Silk was no exception, and silk workers had been making paper since the 2nd century BC. Silk, bamboo, linen, wheat and rice straw were all used differently, and paper made with silk became the first type of luxury paper. Researchers have found an early example of writing done on silk paper in the tomb of a Marchioness who died around 168, in Mawangdui, Changsha, Hunan. The material was certainly more expensive, but also more practical than bamboo slips. Treatises on many subjects, including meteorology, medicine, astrology, divinity, and even maps written on silk[11] have been discovered.

text: During the Han Dynasty, silk became progressively more valuable in its own right, and became more than simply a material. It was used to pay government officials and compensate citizens who were particularly worthy. By the same token that one would sometimes estimate the price of products according to a certain weight of gold, the length of the silk cloth became a monetary standard in China (in addition to bronze coins). The wealth that silk brought to China stirred envy in neighboring peoples. Beginning in the 2nd century BC, the Xiongnu regularly pillaged the provinces of the Han Chinese for around 250 years. Silk was a common offering by the emperor to these tribes in exchange for peace.

text: Silk is described in a chapter on mulberry planting by Si Shengzhi of the Western Han (206 BC – 9 AD). There is a surviving calendar for silk production in an Eastern Han (25–220 AD) document. The two other known works on silk from the Han period are lost.[1]

text: For more than a millennium, silk remained the principal diplomatic gift of the emperor of China to his neighbors or to his vassals.[4] The use of silk became so important that silk (糸) soon constituted one of the principal radicals of Chinese script.

text: Broadly speaking, the use of silk was regulated by a very precise code in China. For example, the Tang Dynasty and Song Dynasty imposed upon bureaucrats the use of particular colors according to their different functions in society. Under the Ming, silk began to be used in a series of accessories: handkerchiefs, wallets, belts, or even an embroidered piece of fabric displaying dozens of animals, real or mythical. These fashion accessories remained associated with a particular position: there was a specific bonnet for warriors, for judges, for nobles, and others for religious use. The women of high Chinese society heeded codified practices and used silk in their garments to which they added countless motifs.[4] A 17th-century work, Jin Ping Mei, gives a description of one such motif:

text: Golden lotus having a quilted backgammon pattern, double-folded, adorned with savage geese pecking at a landscape of flowers and roses; the dress' right figure had a floral border with buttons in the form of bees or chrysanthemums.[4]

text:
Chinese silk making process

The silkworms and mulberry leaves are placed on trays.

Twig frames for the silkworms are prepared.

The cocoons are weighed.

The cocoons are soaked and the silk is wound on spools.

The silk is woven using a loom.

text: Chinese silk and its commerce[edit]

text: Numerous archaeological discoveries show that silk had become a luxury material appreciated in foreign countries well before the opening of the Silk Road by the Chinese. For example, silk has been found in the Valley of the Kings in a tomb of a mummy dating from 1070 BCE.[13] First the Greeks, then the Romans began to speak about the Seres (people of silk), a term to designate the inhabitants of the far-off kingdom, China. According to certain historians, the first Roman contact with silk was that of the legions of the governor of Syria, Crassus. At the Battle of Carrhae, near to the Euphrates, the legions were said to be so surprised by the brilliance of the banners of Parthia that they fled.[13]

text: The silk road toward the west was opened by the Chinese in the 2nd century AD. The main road left from Xi'an, going either to the north or south of the Taklamakan desert, one of the most arid in the world, before crossing the Pamir Mountains. The caravans that employed this method to exchange silk with other merchants were generally quite large, including from 100 to 500 people as well as camels and yaks carrying around 140 kg (300 lb) of merchandise. They linked to Antioch and the coasts of the Mediterranean, about one year's travel from Xi'an. In the South, a second route went by Yemen, Burma, and India before rejoining the northern route.[14][15]

text: Not long after the conquest of Egypt in 30 BC regular commerce began between the Romans and Asia, marked by the Roman appetite for silk cloth coming from the Far East, which was then resold to the Romans by the Parthians. The Roman Senate tried in vain to prohibit the wearing of silk, for economic reasons as well as moral ones. The import of Chinese silk resulted in vast amounts of gold leaving Rome, to such an extent that silk clothing was perceived as a sign of decadence and immorality.

text:
“
I can see clothes of silk, if materials that do not hide the body, nor even one's decency, can be called clothes. ... Wretched flocks of maids labour so that the adulteress may be visible through her thin dress, so that her husband has no more acquaintance than any outsider or foreigner with his wife's body.
”

— Seneca the Younger, Declamations Vol. I.[16]

text: In the late Middle Ages, transcontinental trade over the land routes of the Silk Road declined as sea trade increased.[17] The Silk Road was a significant factor in the development of the civilizations of China, India, Ancient Egypt, Persia, Arabia, and Ancient Rome. Though silk was certainly the major trade item from China, many other goods were traded, and various technologies, religions and philosophies, as well as the bubonic plague (the "Black Death"), also traveled along the Silk Routes. Some of the other goods traded included luxuries such as silk, satin, hemp and other fine fabrics, musk, other perfumes, spices, medicines, jewels, glassware, and even rhubarb, as well as slaves.[18] China traded silk, teas, and porcelain; while India traded spices, ivory, textiles, precious stones, and pepper; and the Roman Empire exported gold, silver, fine glassware, wine, carpets, and jewels. Although the term the Silk Road implies a continuous journey, very few who traveled the route traversed it from end to end; for the most part, goods were transported by a series of agents on varying routes and were traded in the bustling markets of the oasis towns.[18] The main traders during Antiquity were the Indian and Bactrian traders, then from the 5th to the 8th century AD the Sogdian traders, then afterward the Arab and Persian traders.

text: Spread of production[edit]

text: Although silk was well known in Europe and most of Asia, China was able to keep a near monopoly on silk production. The monopoly was defended by an imperial decree, condemning to death anyone attempting to export silkworms or their eggs. Only around the year 300 AD did a Japanese expedition succeed in taking some silkworm eggs and four young Chinese girls, who were forced to teach their captors the art of sericulture.[19] Techniques of sericulture were subsequently introduced to Japan on a larger scale by frequent diplomatic exchanges between the 8th century and 9th centuries.

text: Starting in the 4th century BC silk began to reach the Hellenistic world by merchants who would exchange it for gold, ivory, horses or precious stones. Up to the frontiers of the Roman Empire, silk became a monetary standard for estimating the value of different products. Hellenistic Greece appreciated the high quality of the Chinese goods and made efforts to plant mulberry trees and breed silkworms in the Mediterranean basin. Sassanid Persia controlled the trade of silk destined for Europe and Byzantium. The Greek word for "silken" was σηρικός, from the name of the Seres (Σῆρες), according to Strabo the people from whom silk was first obtained.[20] The Greek word gave rise to Latin sericum and ultimately Old English sioloc, Middle English silk.

text: According to a story by Procopius,[21] it was not until 552 AD that the Byzantine emperor Justinian obtained the first silkworm eggs. He had sent two Nestorian monks to Central Asia, and they were able to smuggle silkworm eggs to him hidden in rods of bamboo. While under the monks' care, the eggs hatched, though they did not cocoon before arrival. The church manufacture in the Byzantine Empire was thus able to make fabrics for the emperor, with the intention of developing a large silk industry in the Eastern Roman Empire, using techniques learned from the Sassanids. These gynecia had a legal monopoly on the fabric, but the empire continued to import silk from other major urban centres on the Mediterranean.[22] The magnificence of the Byzantine techniques was not a result of the manufacturing process, but instead of the meticulous attention paid to the execution and decorations. The weaving techniques they used were taken from Egypt. The first diagrams of semple looms appeared in the 5th century.[23]

text: The Arabs, with their widening conquests, spread sericulture across the shores of the Mediterranean, leading to the development of sericulture in North Africa, Andalusia and Sicily.[24] The interactions among Byzantine and Muslim silk-weaving centers of all levels of quality, with imitations made in Andalusia and Lucca, among other cities, have made the identification and date of rare surviving examples difficult to pinpoint.[25]

text: While the Chinese lost their monopoly on silk production, they were able to re-establish themselves as major silk supplier (during the Tang dynasty), and to industrialize their production in a large scale (during the Song dynasty).[26] China continued to export high-quality fabric to Europe and the Near East along the silk road.

text: After the start of the Crusades, techniques of silk production began to spread across Western Europe. In 1147 while Byzantine emperor Manuel I Komnenos was focusing all his efforts on the Second Crusade, the Norman king Roger II of Sicily attacked Corinth and Thebes, two important centres of Byzantine silk production. They took the crops and silk production infrastructure, and deported all the workers to Palermo, thereby causing the Norman silk industry to flourish.[27] The sack of Constantinople by the Fourth Crusade in 1204 brought decline to the city and its silk industry, and many artisans left the city in the early 13th century.[24] Italy developed a large domestic silk industry after 2000 skilled weavers came from Constantinople. Many also chose to settle in Avignon to furnish the popes of Avignon.

text: The sudden boom of the silk industry in the Italian state of Lucca, starting in the 11th and 12th centuries was due to much Sicilian, Jewish, and Greek settlement, alongside many other immigrants from neighbouring cities in southern Italy.[28] With the loss of many Italian trading posts in the Orient, the import of Chinese styles drastically declined. Gaining momentum, in order to satisfy the rich and powerful bourgeoisie's demands for luxury fabrics, the cities of Lucca, Genoa, Venice and Florence were soon exporting silk to all of Europe. In 1472 there were 84 workshops and at least 7000 craftsmen in Florence alone.

text: Reciprocal influences[edit]

text: Silk was made using various breeds of lepidopterans, both wild and domestic. While wild silks were produced in many countries, there is no doubt that the Chinese were the first to begin production on such a large scale, having the most effective species for silk production, the Bombyx mandarina and its domesticated descendent B. mori. Chinese sources claim the existence of a machine to unwind silkworm cocoons in 1090. The cocoons were placed in a large basin of hot water, the silk would leave the cauldron by tiny guiding rings, and would be wound onto a large spool, thanks to a backwards and forward motion.[10] Little information exists about spinning techniques in use in China. The spinning wheel, in all likelihood moved by hand, was known by the beginning of the Christian era. The first accepted image of a spinning wheel appears in 1210. There is an image of a silk spinning machine powered by a water wheel that dates to 1313.

text: More information is known about the looms used. The Nung Sang Chi Yao, or Fundamentals of Agriculture and Sericulture, compiled around 1210, is rich with pictures and descriptions, many pertaining to silk.[29] It repeatedly claims the Chinese looms to be far superior to all others. It speaks of two types of loom that leave the worker's arms free: the draw loom, which is of Eurasian origin, and the pedal loom which is attributed to East Asian origins. There are many diagrams originate in the 12th and 13th centuries. When examined closely, many similarities between Eurasian machines can be drawn. Since the Jin dynasty, the existence of silk damasks has been well recorded, and since the 2nd century BC, four-shafted looms and other innovations allowed the creation of silk brocades.

text: Silk in the medieval world[edit]

text: A more abundant luxury[edit]

text: The high Middle Ages saw continued use of established techniques for silk manufacture without any changes to speak of, neither in materials nor in tools used. Between the 10th and 12th centuries, small changes began to appear, though the changes of the 13th century were much larger and more radical. In a short time, new fabrics began to appear; hemp and cotton each also had their own particular techniques of manufacture. Known since Roman times, silk remained a rare and expensive material.[30] Byzantine magnaneries in Greece and Syria (6th to 8th century), and those of the Arabs in Sicily and Spain (8th to 10th century) were able to supply the luxury material in a much greater abundance.[30]

text: Improved technology[edit]

text: The 13th century saw an already changing technology undergo many dramatic changes. It is possible that, as with in England at the end of the 18th century, advances in the textile industry were a driving force behind advances in technology as a whole. Silk indeed occupies a privileged place in history on account of this.[31]

text: At the start of the 13th century, a primitive form of milling the silk threads was already in use. In 1221 Jean de Garlande's dictionary, and in 1226, Étienne Boileau's Livre des métiers (Tradesman's Handbook) enumerated many types of devices which can only have been doubling machines. The instruments used were further perfected in Bologna between 1270 and 1280. From the start of the 14th century, many documents allude to the use of devices that were quite complex.[32]

text: The reel, originally developed for the silk industry, now has multiple uses. The earliest surviving depiction of a European spinning wheel is a panel of stained glass in the Cathedral of Chartres.[33] Bobbins and warping machines appear together in the stained glass at Chartres and in a fresco in the Cologne Kunkelhaus (ca 1300). It is possible that the toothed warping machine was created by the silk industry; it allowed the warp to be more uniform and allowed the warp to be of a longer length.[32]

text: Starting at the end of the 14th century, no doubt on account of the devastation caused mid-century by the Black Death, there was a general shift towards less expensive techniques. Many things which would have earlier been completely forbidden by the guilds were now commonplace (using low quality wool, carding, etc.). In the silk industry, the use of water-powered mills grew, and by the 15th century, the loom designed by Jean le Calabrais saw nearly universal use.[34]

text: The silk industry in France[edit]

text: Italian silk cloth was very expensive, as much a result of the cost of the raw material as of the production costs. The craftsmen in Italy proved unable to keep up with the exigencies of French fashion, which continuously demanded lighter and less expensive materials.[35] These materials were used for clothing, and garment production began to be done locally. Nevertheless, Italian silk long remained among the most prized, mostly for furnishings and the brilliant colours of the dyes.

text: Following the example of the wealthy Italian city-states of the era, such as Venice, Florence, and Lucca, which had become the center of the luxury-textile industry, Lyon obtained a similar function in the French market. In 1466, King Louis XI decided to develop a national silk industry in Lyon. In the face of protests by the Lyonnais, he conceded and moved the silk fabrication to Tours, but the industry in Tours stayed relatively marginal. His main objective was to reduce France's trade deficit with the Italian states, which caused France to lose 400,000 to 500,000 golden écus a year.[36] It was under Francis I in around 1535 that a royal charter was granted to two merchants, Étienne Turquet and Barthélemy Naris, to develop a silk trade in Lyon. In 1540, the king granted a monopoly on silk production to the city of Lyon. Starting in the 16th century, Lyon became the capital of the European silk trade, notably producing many reputable fashions.[37] Gaining confidence, the silks produced in the city began to abandon the original oriental styles in favor of their own distinctive style, which emphasized landscapes. Thousand of workers, the canuts, devoted themselves to the flourishing industry. In the middle of the 17th century, over 14,000 looms were used in Lyon, and the silk industry fed a third of the city's population.[37]

text: In the 18th and 19th centuries, Provence experienced a boom in sericulture that would last until the first world war, with much of the silk shipped north to Lyon. Viens and La Bastide-des-Jourdans are two of the communes of Luberon that profited the most from mulberry plantations that have since disappeared.[38] However, silk centers still operate today.[39]Working at home under the domestic system, silk spinning and silk treatment employed many people and increased the income of the working class.

text: Spread to other countries[edit]

text: England under Henry IV was also looking to develop a silk industry, but no opportunity arose until the revocation of the Edict of Nantes the 1680s, when hundreds of thousands of French Huguenots, many of whom were skilled weavers and experts in sericulture, began immigrating to England to escape religious persecution. Some areas, including Spitalfields saw many high-quality silk workshops spring up, their products distinct from continental silk largely by the colors used.[40] Nonetheless, the British climate prevented England's domestic silk trade from becoming globally dominant.

text: Many envisioned starting a silk industry in the British colonies in America, starting in 1619, under the reign of King James I of England. The silk industry in the colonies never became very large. Likewise, silk was introduced to numerous other countries, including Mexico, where it was brought by Cortez in 1522. Only rarely did these new silk industries grow to any significant size.[41]

text: Silk since the Industrial Revolution[edit]

text: The start of the Industrial Revolution[edit]

text: The start of the Industrial Revolution was marked by a massive boom in the textile industry, with remarkable technological innovations made, led by the cotton industry of Great Britain. In its early years, there were often disparities in technological innovation between different stages of fabric manufacture, which encouraged complementary innovations. For example, spinning progressed much more rapidly than weaving.

text: The silk industry, however, did not gain any benefit from innovations in spinning, as silk is naturally already a thread. Making silk, silver, and gold brocades is a very delicate and precise process, with each colour needing its own dedicated shuttle. In the 17th century and 18th centuries progress began to be made in the simplification and standardization of silk manufacture, with many advances following one after another. Bouchon and Falcon's punched card loom appeared in 1775, later improved on by Jacques de Vaucanson. Later, Joseph-Marie Jacquard improved on the designs of Falcon and Vaucanson, introducing the revolutionary Jacquard loom, which allowed a string of punched cards to be processed mechanically in the correct sequence.[42] The punched cards of the Jacquard loom were a direct precursor to the modern computer, in that they gave a (limited) form of programmability. Punched cards themselves were carried over to computers, and were ubiquitous until their obsolescence in the 1970s. From 1801 embroidery became highly mechanized due to the effectiveness of the Jacquard loom. The mechanism behind the Jacquard loom even allowed complex designs to be mass-produced.

text: The Jacquard loom was immediately denounced by workers, who accused it of causing unemployment, but soon it had become vital to the industry. The loom was declared public property in 1806, and Jacquard was rewarded with a pension and a royalty on each machine. In 1834 there were a total of 2885 Jacquard looms in Lyon alone.[37] The Canut revolt in 1831 foreshadowed many of the larger worker uprisings of the Industrial Revolution. The canuts occupied the city of Lyon, and would not relinquish it until a bloody repression by the army, led by Marshal Soult. A second revolt, similar to the first, took place in 1834.

text: Decline in the European silk industry[edit]

text: The first silkworm diseases began to appear in 1845, creating an epidemic. Among them are pébrine, caused by the microsporidia Nosema bombycis, grasserie, caused by a virus, flacherie, caused by eating infected mulberry leaves or white muscardine disease, caused by the fungus Beauveria bassiana. The epidemic grew to a massive scale, and after having attacked the silkworms, other viruses began to infect the mulberry trees. The chemist Jean-Baptiste Dumas, French minister of agriculture, was charged with stopping the epidemic. In face of sericulturers' call for help, he asked Louis Pasteur to study the disease, starting in 1865.[43] For many years, Pasteur thought that pébrine was not a contagious disease. In 1870 he changed his view, and measures were enacted that caused the disease to decline.

text: Nevertheless, the increase in the price of silkworm cocoons and the reduction in importance of silk in the garments of the bourgeoisie in the 19th century caused the decline of the silk industry in Europe. The opening of the Suez Canal in 1869 and the silk shortage in France reduced the price of importing Asian silk, particularly from China and Japan.[44]

text: Starting from the Long Depression (1873–1896), Lyonnais silk production had become totally industrialized, and hand looms were rapidly disappearing. The 19th century saw the textile industry's progress caused by advances in chemistry. The synthesis of aniline was used to make mauveine (aniline purple) dye and the synthesis of quinine was used to make indigo dye. In 1884 Count Hilaire de Chardonnet invented artificial silk and in 1891 opened a factory dedicated to the production of artificial silk (viscose), which cost much less and in part replaced natural silk.

text:
A Jacquard loom.

An illustration of spinning, winding, doubling and throwing machines used in silk textile production in England, 1858.

Silk, cotton and gilt-metal-strip-wrapped cotton panel, machine-woven in Scotland c. 1887. Tulip motif is inspired by Turkish textiles.

text: Silk in modern times[edit]

text: Following the crisis in Europe, the modernization of sericulture in Japan made it the world's foremost silk producer. By the early 20th century, rapidly industrializing Japan was producing as much as 60 percent of the world's raw silk, most exports shipping through the port of Yokohama.[45] Italy managed to rebound from the crisis, but France was unable. Urbanization in Europe saw many French and Italian agricultural workers leave silk growing for more lucrative factory work. Raw silk was imported from Japan to fill the void.[6] Asian countries, formerly exporters of raw materials (cocoons and raw silk), progressively began to export more and more finished garments.

text: During the Second World War, silk supplies from Japan were cut off, so western countries were forced to find substitutes. Synthetic fibres such as nylon were used in products such as parachutes and stockings, replacing silk. Even after the war, silk was not able to regain many of the markets lost, though it remained an expensive luxury product.[6] Postwar Japan, through improvements in technology and a protectionist market policy, became the world's foremost exporter of raw silk, a position it held until the 1970s.[6] The continued rise in importance of synthetic fibres and loosening of the protectionist economy contributed to the decline of Japan's silk industry, and by 1975 it was no longer a net exporter of silk.[46]

text: With its recent economic reforms, the People's Republic of China has become the world's largest silk producer. In 1996 it produced 58,000 tonnes out of a world production of 81,000, followed by India at 13,000 tonnes. Japanese production is now marginal, at only 2500 tonnes. Between 1995 and 1997 Chinese silk production went down 40% in an effort to raise prices, reminiscent of earlier shortages.[47]

text: In December 2006 the General Assembly of the United Nations proclaimed 2009 to be the International Year of Natural Fibres, so as to raise the profile of silk and other natural fibres.

text: Notes[edit]

text:
^ Jump up to: a b Vainker, Shelagh (2004). Chinese Silk: A Cultural History. Rutgers University Press. pp. 20, 17. ISBN 0813534461.
Jump up ^ Tang, Chi and Miao, Liangyun, "Zhongguo Sichoushi" ("History of Silks in China") Archived 2007-11-23 at the Wayback Machine.. Encyclopedia of China, 1st ed.
Jump up ^ "Textile Exhibition: Introduction". Asian art. Retrieved 2007-08-02.
^ Jump up to: a b c d e f (in French) Charles Meyer, Des mûriers dans le jardin du mandarin, Historia, n°648, December 2000.
^ Jump up to: a b c (in French) "Soie'" (§2. Historique), Encyclopédie Encarta
^ Jump up to: a b c d "The History of Silk". The Silk Association of Great Britain. Archived from the original on 2007-09-29. Retrieved 2007-10-23.
Jump up ^ Hill (2009), "Appendix A: Introduction of Silk Cultivation to Khotan in the 1st Century AD.", pp. 466-467.
Jump up ^ Jean-Noël Robert. "Les relations entre le monde romain et la Chine : la tentation du Far East" (in French). clio.fr. Archived from the original on May 22, 2007. Retrieved May 6, 2007.
Jump up ^ Pliny the Elder, Naturalis Historia 11.xxvi.76
^ Jump up to: a b (in French) Histoire des techniques p.455
Jump up ^ Plous, Estelle. "A History of Silk Maps". TravelLady Magazine. Archived from the original on 2007-09-28. Retrieved 2007-05-20.
Jump up ^ Liu (2010), p. 12.
^ Jump up to: a b "History of Silk". Silk road Foundation. Retrieved 2007-03-08.
Jump up ^ (in French) "Histoire de la Route de la soie", Encyclopædia Universalis
Jump up ^ (in French) Charles Meyer, "Les routes de la soie : 22 siècles d'aventure", Historia, n°648 December 2000.
Jump up ^ Seneca the Younger, Declamations Vol. I.
Jump up ^ Hogan, C. Michael. "The Megalithic Portal and Megalith Map: Silk Road, North China [Northern Silk Road, North Silk Road] Ancient Trackway". www.megalithic.co.uk. Retrieved 2008-07-05.
^ Jump up to: a b Wood, Francis (2002). The Silk Road: Two Thousand Years in the Heart of Asia. Berkeley, CA: University of California Press. pp. 9, 13–23. ISBN 978-0-520-24340-8.
Jump up ^ Cook, (1999), 144.
Jump up ^ Strabo 11.11.1, 15.1.34. The adjective σηρικός is recorded in the 2nd century CE, found in Lucian ( De saltatione 63), Cassius Dio (43.24), Pausanias (6.26.6).
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Jump up ^ (in French) Histoire des Techniques p.435
^ Jump up to: a b (in French) Anne Kraatz, Marie Risselin-Steenebrugen, Michèle Pirazzoli-t’Serstevens and Madeleine Paul-David (2006), "Tissus d'art", in Encyclopædia Universalis
Jump up ^ David Jacoby, "Silk Economics and Cross-Cultural Artistic Interaction: Byzantium, the Muslim World, and the Christian West", Dumbarton Oaks Papers 58 (2004), pp. 197-240.
Jump up ^ Heleanor B. Feltham: Justinian and the International Silk Trade, p. 34
Jump up ^ (in French) Georges Ostrogorsky, Histoire de l’état byzantin, Payot, 1956, reedited in 1977, ISBN 2-228-07061-0
Jump up ^ (in French) Histoire des techniques p.551
Jump up ^ Joseph Needham, Francesca Bray, Hsing-Tsung Huang, Christian Daniels, Nicholas K. Menzies, Science and Civilisation in China, Cambridge University Press, 1984 p. 72 ISBN 0-521-25076-5
^ Jump up to: a b Xinru Liu, Silk and Religion: An Exploration of Material Life and the Thought of People AD 600-1200, Oxford University Press US, 1998.
Jump up ^ (in French) Histoire des Techniques p.553
^ Jump up to: a b (in French) Histoire des Techniques p.557
Jump up ^ Ronan (1994), 68,
Jump up ^ (in French) Histoire des Techniques p.639
Jump up ^ (in French) Autour du Fil, l'encyclopédie des arts textiles
Jump up ^ (in French) Georges Duby (ed), Histoire de la France : Dynasties et révolutions, de 1348 à 1852 (vol. 2), Larousse, 1999 p. 53 ISBN 2-03-505047-2
^ Jump up to: a b c (in French) Gérard Chauvy, "La dure condition des forçats du luxe", Historia, n°648, December 2000
Jump up ^ (in French) Guide Gallimard - Parc naturel LUBERON
Jump up ^ Waters, Sarah. “The Silk Industry in Lyon, France.” Museum of the City. Accessed 6 October 2017. http://www.museumofthecity.org/project/the-silk-industry-in-lyon-france/
Jump up ^ Thirsk (1997), 120.
Jump up ^ Peter N. Stearns, William Leonard Langer The Encyclopedia of World History, Houghton Mifflin Books, 2001 p. 403 ISBN 0-395-65237-5
Jump up ^ (in French) Histoire des techniques p.718
Jump up ^ "Louis Pasteur," Microsoft Encarta Online Encyclopedia 2007. Archived 2009-11-01.
Jump up ^ A. J. H. Latham and Heita Kawakatsu, Japanese Industrialization and the Asian Economy p. 199
Jump up ^ Reilly, Benjamin (2009). Disaster and Human History: Case Studies in Nature, Society and Catastrophe. Jefferson N.C.: McFarland & Company Inc. p. 95. ISBN 978-0-7864-3655-2.
Jump up ^ "The Cocoon Strikes Back: Innovative Products Could Revive a Dying Industry". Japan Information Network. 2000. Retrieved October 23, 2007.
Jump up ^ Anthony H. Gaddum, "Silk", Business and Industry Review, (2006). In Encyclopædia Britannica


document_title: Tom Welling

question_text: who plays charlie in cheaper by the dozen

root

text: Tom Welling

text: Early life[edit]

text: Welling was born in Putnam Valley, New York.[2][4] His family moved frequently, making stops in Wisconsin, Delaware, and Michigan.[4] Welling attended Okemos High School in Okemos, Michigan, where he started acting in plays, but then switched into sports. Welling played baseball and soccer, but his favorite sport is basketball.[4] Welling is one of four children, with two older sisters, Rebecca and Jamie,[5] and a younger brother, Mark Welling, who is also an actor.[2]

tag: p

text: Career[edit]

text: Early career[edit]

text: Originally a construction worker, Welling was discovered in 1998 at a party in Nantucket by a catalog camera scout who suggested he try modeling.[2] Welling modelled for Louisa Modeling Agency until 2000,[4] when he relocated to Los Angeles. There he modelled for Tommy Hilfiger, Abercrombie & Fitch, and Calvin Klein while pursuing an acting career.[2] In 2000, Welling appeared in Angela Via's music video "Picture Perfect" where he played Vía's love interest. Welling has stated that he did not like modelling and that he was not good at it because it was all on the outside or from an external point of view. He pursued acting because he wanted to express a range of emotions,[5] but Welling still models occasionally and appeared in the May 2008 issue of Vogue, the so-called Superhero Issue.[6] In his first major acting role, Welling played karate teacher Rob "Karate Rob" Meltzer, a younger love interest of Amy Gray (Amy Brenneman) in the second season of the CBS legal drama Judging Amy, which aired in 2001. Welling was originally signed for three episodes; after receiving enthusiastic fan reviews, the producers kept him for three more.[4] Welling also had a small role in the UPN science fiction sitcom Special Unit 2, and he appeared in the pilot episode of the FOX sitcom Undeclared.[4]

text: Smallville[edit]

text: Welling was cast in the WB superhero drama Smallville after a nationwide search for an actor to play Clark Kent. In an interview with a teen magazine, Welling spoke about the day he auditioned for the role: "I was on my way back from the Warner Bros. studio, and I stopped in a gas station to call my manager and tell him how it went. I called and got him on the phone and he said, 'Can you hold on a second?' Next thing I know, there are literally seven people on the other line and almost in unison they say, 'Tom, you got it!'"[4] The pilot aired in October 2001 and became the highest-rated debut for The WB, with 8.4 million viewers.[7] Welling told TV Guide that he turned down the lead role twice, but after reading the script, decided to take the job. Like Christopher Reeve, he was not a Superman fan prior to being cast as Clark Kent. In fact, he said, he continues to not read Superman comics: "I made a conscious decision to stay away from that material. We're doing something different at a time before all that, I don't want that to affect what I'm doing, even subconsciously."[8] He did get the chance to meet two previous Superman actors: Christopher Reeve, who appeared in season 2: episode 17 titled "Rosetta", and Dean Cain, who appeared in season 7: episode 4 titled "Cure".[9]

text: Welling was named one of People magazine's "Breakthrough Stars of 2001", and also won the Teen Choice Award as "Choice Breakout Star (Male)" in 2002 for his role as Clark Kent.[10] Following the third season, Welling was interviewed by Smallville Magazine and stated that if he could play one character on the show that was not Clark Kent, it would be Lex Luthor; "Lex Luthor! I wouldn’t mind having my head shaved—as an actor, [it is the ultimate,] getting to play the complete opposite of your character."[11]

text: In 2004, Welling was approached about starring in the big screen adaptation of Superman when director Brett Ratner was attached to the project. Comic book artist Alex Ross even did two sketches of Welling as the "Man of Steel" to see what the actor would look like in the famous costume.[12] In August 2009, Welling won another Teen Choice Award as "Choice TV Actor (Action Adventure)" for Smallville.[13]

text: Lucifer[edit]

text: In 2017, Welling was cast as a series regular on the Fox television series Lucifer for the third season. He plays Marcus Pierce, a police lieutenant at the precinct who is actually the immortal Cain, the first murderer, cursed by God to walk the Earth for eternity.[14]

text: Film[edit]

text: In December 2003, Welling made his feature film debut as Charlie Baker, the oldest son and second-oldest in the Baker family which had 12 children, in the family comedy Cheaper by the Dozen with Steve Martin and Bonnie Hunt, which is a remake of the 1950 movie starring Clifton Webb and Myrna Loy, based on the 1948 book about the family of Frank and Lillian Gilbreth and written by two of their children.[10] Welling talked about why he was interested in the project in an interview with Paul Fischer: "The top three reasons I decided to do this film were, one, Steve Martin, two, Steve Martin and three, Steve Martin. That was the number one draw for me. Then, after reading the script, I really liked this character, Charlie. I liked what he went through, what he had to go through, and I felt I understood where he was coming from. And I just wanted to be a part of it."[5] Welling had always been a fan of Martin's and stated that he "absolutely loved" working with him.[5]

text: In 2005, Welling co-starred in the horror film The Fog, a remake of John Carpenter's 1980 film of the same name, as Nick Castle (a character originally played by Tom Atkins).[15] At the same time The Fog was in production, Welling was still working on the last few episodes of the fourth season of Smallville. The same year, he reprised his role as Charlie Baker in Cheaper by the Dozen 2.

text: In 2013, Welling was among the all-star cast of Peter Landesman's historical drama Parkland, based on the book Reclaiming History: The Assassination of President John F. Kennedy by author Vincent Bugliosi. The story centers on the chaotic events that occurred at Parkland Hospital in Dallas, Texas on the day President John F. Kennedy was assassinated on November 22, 1963.[16] In 2014, Welling co-starred with Kevin Costner, Jennifer Garner, Frank Langella, and Denis Leary in Ivan Reitman's sports drama Draft Day. He played a veteran quarterback whose career is at a crossroads.

text: Production[edit]

text: For Smallville's ninth season, Welling served as a co-executive producer.[10] He returned as Clark Kent for the show's tenth and final season in Fall 2010 and became a full executive producer, as credited in a May 20, 2010 press release by the CW.[17]

text: Welling served as an executive producer on the CW comedy-drama Hellcats based on journalist Kate Torgovnick's book Cheer: Inside the Secret World of College Cheerleaders.[18][19] The series first aired on The CW beginning in the fall of 2010,[17] and was cancelled on May 17, 2011. It is currently available to watch for free on CW Seed, CW's digital programming.[20] According to Welling, he states that the reason of cancellation was due to the change of CW president of entertainment from Dawn Ostroff to Mark Pedowitz. He also said that there was a possibility of a reboot of the series with a new cast and cameos from the previous cast if enough fans continue to watch the original series on CW Seed.[21]

text: Directing[edit]

text: Welling made his directorial debut in 2006 with the Smallville episode "Fragile" (5.18). He also directed "Hydro" (6.10); the show's 150th episode, "Apocalypse" (7.18); "Injustice" (8.21); the second part ("Legends") of the two-hour episode "Absolute Justice" (9.11); and two episodes of Smallville's final season, "Patriot" (10.09) and "Booster" (10.18).

text: Personal life[edit]

text: On July 5, 2002, Welling married model Jamie White[2] on Martha's Vineyard with Welling's friends and then-Smallville co-stars Kristin Kreuk and Michael Rosenbaum in attendance.[22] Welling and White resided in Vancouver, British Columbia, Canada,[5] but returned to Los Angeles in March 2011. On October 17, 2013, White filed for divorce from Welling. The divorce was finalized in November 2015.[23]

text: Welling plays golf in his spare time.[24][25] Welling has stated in YM that he dislikes interviews. He said, "I don't want to be a celebrity for the sake of being a celebrity. I want to work and then go home and live in private."[26] Welling has also said he disliked being a model because it wasn't fulfilling and wasn't an expressive job.[27]

text: Filmography[edit]

text:
Film

Year

Title

Role

Notes

2003

Cheaper by the Dozen

Charlie Baker

Nominated – Teen Choice Award Choice Movie: Male Breakout Star

2005

The Fog

Nicholas "Nick" Castle

2005

Cheaper by the Dozen 2

Charlie Baker

2013

Parkland

Secret Service Agent Roy Kellerman

2014

Draft Day

Brian Drew

2016

The Choice

Dr. Ryan McCarthy

tag: table

text:
Television

Year

Title

Role

Notes

2001

Judging Amy

Rob Meltzer

Recurring role (Season 2); 6 episodes

2001

Special Unit 2

Male victim

Episode: "The Depths"

2001

Undeclared

Tom

Episode: "Prototype"

2001–2011

Smallville

Kal-El/Clark Kent/SupermanYoung Jor-ElBizarroKal-El/Clark Luthor/Ultraman

Lead role; 218 EpisodesChoice TV Actor: Action (2009)Teen Choice Award for Choice TV: Male Breakout Stars(2002)Nominated – Choice TV Actor: Fantasy/Sci-Fi (2010-2011)Nominated – Scream Awards for Best Superhero (2010-2011)Nominated – Choice TV Actor: Action (2003-2008)Nominated – Teen Choice Award for Choice TV: Chemistry (shared w/Kristin Kreuk) (2006)Nominated – Saturn Award for Best Actor on Television (2002-2006)Nominated – Choice TV Actor: Drama (2002, 2005)

2015

Man Fire Food

Himself

Episode: "Backyard Blowouts"

2017–present

Lucifer

Lt. Marcus Pierce / Cain

Main cast (season 3)

text:
List of director and producer credits

Year

Title

Notes

2006–2011

Smallville

Director  Episode 5.18 "Fragile"  Episode 6.10 "Hydro"  Episode 7.18 "Apocalypse"  Episode 8.21 "Injustice"  Episode 9.11 "Absolute Justice"  Episode 10.09 "Patriot"  Episode 10.18 "Booster"

2009–2010

Smallville

Co-executive producer  22 episodes (Season 9)

2010–2011

Smallville

Executive producer  22 episodes (Season 10)

2010–2011

Hellcats

Executive producer  18 episodes (Season 1)

text:
Music video

Year

Title

Artist

Role

2000

"Picture Perfect"

Angela Via

Vía's love interest


document_title: Group 12 element

question_text: what do sodium and magnesium have in common

text: Group 12 element

text: Physical and atomic properties[edit]

text: Like other groups of the periodic table, the members of group 12 show patterns in its electron configuration, especially the outermost shells, which result in trends in their chemical behavior:

text:
Z
Element
No. of electrons/shell

30
zinc
2, 8, 18, 2

48
cadmium
2, 8, 18, 18, 2

80
mercury
2, 8, 18, 32, 18, 2

112
copernicium
2, 8, 18, 32, 32, 18, 2 (predicted)

text: Group 12 elements are all soft, diamagnetic, divalent metals. They have the lowest melting points among all transition metals.[8] Zinc is bluish-white and lustrous,[9] though most common commercial grades of the metal have a dull finish.[10] Zinc is also referred to in nonscientific contexts as spelter.[citation needed] Cadmium is soft, malleable, ductile, and with a bluish-white color. Mercury is a liquid, heavy, silvery-white metal. It is the only common liquid metal at ordinary temperatures, and as compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity.[11]

text: The table below is a summary of the key physical properties of the group 12 elements. Very little is known about copernicium, and none of its physical properties have been confirmed except for its boiling point (tentative).[12]

text:
Properties of the group 12 elements

Name
Zinc
Cadmium
Mercury
Copernicium

Melting point
693 K (420 °C)
594 K (321 °C)
234 K (−39 °C)
 ?

Boiling point
1180 K (907 °C)
1040 K (767 °C)
630 K (357 °C)
357+112
−108 K (84+112
−108 °C)

Density
7.14 g·cm−3
8.65 g·cm−3
13.534 g·cm−3
 ? 23.7 g·cm−3

Appearance
silvery bluish-gray metallic
silver-gray
silvery
 ?

Atomic radius
135 pm
155 pm
150 pm
 ? 147 pm

text: Zinc is somewhat less dense than iron and has a hexagonal crystal structure.[13] The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C.[9][10] Above 210 °C, the metal becomes brittle again and can be pulverized by beating.[14] Zinc is a fair conductor of electricity.[9] For a metal, zinc has relatively low melting (419.5 °C, 787.1 F) and boiling points (907 °C).[8] Cadmium is similar in many respects to zinc but forms complex compounds.[15] Unlike other metals, cadmium is resistant to corrosion and as a result it is used as a protective layer when deposited on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable; however, in its powdered form it may burn and release toxic fumes.[16] Mercury has an exceptionally low melting temperature for a d-block metal. A complete explanation of this fact requires a deep excursion into quantum physics, but it can be summarized as follows: mercury has a unique electronic configuration where electrons fill up all the available 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d and 6s subshells. As such configuration strongly resists removal of an electron, mercury behaves similarly to noble gas elements, which form weak bonds and thus easily melting solids. The stability of the 6s shell is due to the presence of a filled 4f shell. An f shell poorly screens the nuclear charge that increases the attractive Coulomb interaction of the 6s shell and the nucleus (see lanthanide contraction). The absence of a filled inner f shell is the reason for the somewhat higher melting temperature of cadmium and zinc, although both these metals still melt easily and, in addition, have unusually low boiling points. Gold has atoms with one less 6s electron than mercury. Those electrons are more easily removed and are shared between the gold atoms forming relatively strong metallic bonds.[17][18]

text:
Zinc, cadmium and mercury form a large range of alloys. Among the zinc containing ones, brass is an alloy of zinc and copper. Other metals long known to form binary alloys with zinc are aluminium, antimony, bismuth, gold, iron, lead, mercury, silver, tin, magnesium, cobalt, nickel, tellurium and sodium.[19] While neither zinc nor zirconium are ferromagnetic, their alloy ZrZn
2 exhibits ferromagnetism below 35 K.[9] Cadmium is used in many kinds of solder and bearing alloys, due to a low coefficient of friction and fatigue resistance.[20] It is also found in some of the lowest-melting alloys, such as Wood's metal.[21] Because it is a liquid, mercury dissolves other metals and the alloys that are formed are called amalgams. For example, such amalgams are known with gold, zinc, sodium, and many other metals. Because iron is an exception, iron flasks have been traditionally used to trade mercury. Other metals that do not form amalgams with mercury include tantalum, tungsten and platinum. Sodium amalgam is a common reducing agent in organic synthesis, and is also used in high-pressure sodium lamps. Mercury readily combines with aluminium to form a mercury-aluminium amalgam when the two pure metals come into contact. Since the amalgam reacts with air to give aluminium oxide, small amounts of mercury corrode aluminium. For this reason, mercury is not allowed aboard an aircraft under most circumstances because of the risk of it forming an amalgam with exposed aluminium parts in the aircraft.[22]

text: Chemistry[edit]

text: Most of the chemistry has been observed only for the first three members of the group 12. The chemistry of copernicium is not well established and therefore the rest of the section deals only with zinc, cadmium and mercury.

text: Periodic trends[edit]

text: All elements in this group are metals. The similarity of the metallic radii of cadmium and mercury is an effect of the lanthanide contraction. So, the trend in this group is unlike the trend in group 2, the alkaline earths, where metallic radius increases smoothly from top to bottom of the group. All three metals have relatively low melting and boiling points, indicating that the metallic bond is relatively weak, with relatively little overlap between the valence band and the conduction band.[23] Thus, zinc is close to the boundary between metallic and metalloid elements, which is usually placed between gallium and germanium, though gallium participates in semi-conductors such as gallium arsenide.

text:
Zinc and cadmium are electropositive while mercury is not.[23] As a result, zinc and cadmium metal are good reducing agents. The elements of group 12 have an oxidation state of +2 in which the ions have the rather stable d10 electronic configuration, with a full sub-shell. However, mercury can easily be reduced to the +1 oxidation state; usually, as in the ion Hg2+
2, two mercury(I) ions come together to form a metal-metal bond and a diamagnetic species.[24] Cadmium can also form species such as [Cd2Cl6]4− in which the metal's oxidation state is +1. Just as with mercury, the formation of a metal-metal bond results in a diamagnetic compound in which there are no unpaired electrons; thus, making the species very reactive. Zinc(I) is known only in the gas phase, in such compounds as linear Zn2Cl2, analogous to calomel.

text: Classification[edit]

text: The elements in group 12 are usually considered to be d-block elements, but not transition elements as the d-shell is full. Some authors classify these elements as main-group elements because the valence electrons are in ns2 orbitals. Nevertheless, they share many characteristics with the neighboring group 11 elements on the periodic table, which are almost universally considered to be transition elements. For example, zinc shares many characteristics with the neighboring transition metal, copper. Zinc complexes merit inclusion in the Irving-Williams series as zinc forms many complexes with the same stoichiometry as complexes of copper(II), albeit with smaller stability constants.[25] There is little similarity between cadmium and silver as compounds of silver(II) are rare and those that do exist are very strong oxidizing agents. Likewise the common oxidation state for gold is +3, which precludes there being much common chemistry between mercury and gold, though there are similarities between mercury(I) and gold(I) such as the formation of linear dicyano complexes, [M(CN)2]−. According to IUPAC's definition of transition metal as an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell,[26] zinc and cadmium are not transition metals, while mercury is. This is because only mercury is known to have a compound where its oxidation state is higher than +2, in mercury(IV) fluoride (though its existence is disputed, as later experiments trying to confirm its synthesis could not find evidence of HgF4).[27][28] However, this classification is based on one highly atypical compound seen at non-equilibrium conditions and is at odds to mercury's more typical chemistry, and Jensen has suggested that it would be better to regard mercury as not being a transition metal.[29]

text: Relationship with the alkaline earth metals[edit]

text: Although group 12 lies in the d-block of the modern 18-column periodic table, the d electrons of zinc, cadmium, and (almost always) mercury behave as core electrons and do not take part in bonding. This behavior is similar to that of the main-group elements, but is in stark contrast to that of the neighboring group 11 elements (copper, silver, and gold), which also have filled d-subshells in their ground-state electron configuration but behave chemically as transition metals. For example, the bonding in chromium(II) sulfide (CrS) involves mainly the 3d electrons; that in iron(II) sulfide (FeS) involves both the 3d and 4s electrons; but that of zinc sulfide (ZnS) involves only the 4s electrons and the 3d electrons behave as core electrons. Indeed, useful comparison can be made between their properties and the first two members of group 2, beryllium and magnesium, and in earlier short-form periodic table layouts, this relationship is illustrated more clearly. For instance, zinc and cadmium are similar to beryllium and magnesium in their atomic radii, ionic radii, electronegativities, and also in the structure of their binary compounds and their ability to form complex ions with many nitrogen and oxygen ligands, such as complex hydrides and amines. However, beryllium and magnesium are small atoms, unlike the heavier alkaline earth metals and like the group 12 elements (which have a greater nuclear charge but the same number of valence electrons), and the periodic trends down group 2 from beryllium to radium (similar to that of the alkali metals) are not as smooth when going down from beryllium to mercury (which is more similar to that of the p-block main groups) due to the d-block and lanthanide contractions. It is also the d-block and lanthanide contractions that give mercury many of its distinctive properties.[29]

text:
Comparison of the properties of the alkaline earth metals and the group 12 elements[29]

Name
Beryllium
Magnesium
Calcium
Strontium
Barium
Radium

Valence electron configuration
2s2
3s2
4s2
5s2
6s2
7s2

Core electron configuration
[He]
[Ne]
[Ar]
[Kr]
[Xe]
[Rn]

Oxidation states[note 1]
+2, +1
+2, +1
+2, +1
+2, +1
+2
+2

Melting point
1560 K (1287 °C)
923 K (650 °C)
1115 K (842 °C)
1050 K (777 °C)
1000 K (727 °C)
973 K (700 °C)

Boiling point
2742 K (2469 °C)
1363 K (1090 °C)
1757 K (1484 °C)
1655 K (1382 °C)
2170 K (1897 °C)
2010 K (1737 °C)

Appearance
white-gray metallic
shiny gray metallic
dull silver-gray
silvery white metallic
silvery gray
silvery white metallic

Density
1.85 g·cm−3
1.738 g·cm−3
1.55 g·cm−3
2.64 g·cm−3
3.51 g·cm−3
5.5 g·cm−3

Pauling electronegativity
1.57
1.31
1.00
0.95
0.89
0.9

Atomic radius
105 pm
150 pm
180 pm
200 pm
215 pm
215 pm

Crystal ionic radius
59 pm
86 pm
114 pm
132 pm
149 pm
162 pm

Flame test color
white[29]
brilliant white[30]
brick-red[30]
crimson[30]
apple green[30]
crimson red[note 2]

Organometallic chemistry
good
good
poor
very poor
very poor
extremely poor

Hydroxide
amphoteric
basic
basic
strongly basic
strongly basic
strongly basic

Oxide
amphoteric
strongly basic
strongly basic
strongly basic
strongly basic
strongly basic

Name
Beryllium
Magnesium
Zinc
Cadmium
Mercury
Copernicium

Valence electron configuration
2s2
3s2
4s2
5s2
6s2
 ? 7s2

Core electron configuration
[He]
[Ne]
[Ar]3d10
[Kr]4d10
[Xe]4f145d10
 ? [Rn]5f146d10

Oxidation states[note 1]
+2, +1
+2, +1
+2, +1
+2, +1
+4, +2, +1
 ? +4, +2, +1, 0[32][33][34]

Melting point
1560 K (1287 °C)
923 K (650 °C)
693 K (420 °C)
594 K (321 °C)
234 K (−39 °C)
 ?

Boiling point
2742 K (2469 °C)
1363 K (1090 °C)
1180 K (907 °C)
1040 K (767 °C)
630 K (357 °C)
357+112
−108 K (84+112
−108 °C)

Appearance
white-gray metallic
shiny gray metallic
silvery bluish-gray metallic
silver-gray
silvery
 ?

Density
1.85 g·cm−3
1.738 g·cm−3
7.14 g·cm−3
8.65 g·cm−3
13.534 g·cm−3
 ? 23.7 g·cm−3[33]

Pauling electronegativity
1.57
1.31
1.65
1.69
2.00
 ?

Atomic radius
105 pm
150 pm
135 pm
155 pm
150 pm
 ? 147 pm[33]

Crystal ionic radius
59 pm
86 pm
88 pm
109 pm
116 pm
 ? 75 pm[33]

Flame test color
white
brilliant white
bluish-green[note 3]
 ?
 ?
 ?

Organometallic chemistry
good
good
good
good
good
 ?

Hydroxide
amphoteric
basic
amphoteric
weakly basic
 ?
 ?

Oxide
amphoteric
strongly basic
amphoteric
mildly basic
mildly basic
 ?

text: Compounds[edit]

text:
All three metal ions form many tetrahedral species, such as MCl2−
4. Both zinc and cadmium can also form octahedral complexes such as the aqua ions [M(H2O)6]2+ which are present in aqueous solutions of salts of these metals.[35] Covalent character is achieved by using the s and possibly p orbitals. Mercury, however, rarely exceeds a coordination number of four. Coordination numbers of 2, 3, 5, 7 and 8 are also known.

text: Extensions[edit]

text:
Although copernicium is the heaviest known group 12 element, there has been some theoretical work regarding possible heavier group 12 elements. Although a simple extrapolation of the periodic table would put element 162, unhexbium (Uhb), under copernicium, relativistic Dirac-Fock calculations predict that the next group 12 element after copernicium should actually be element 164, unhexquadium (Uhq), which is predicted to have an electron configuration of [Og] 5g18 6f14 7d10 8s2 8p1/22.[33][36] The 8s and 8p1/2 orbitals are predicted to be so strongly stabilized relativistically that they become core electrons and do not participate in chemical reactions, unlike the earlier group 12 elements where the s electrons behave as valence electrons. However, the 9s and 9p1/2 levels are expected to be readily available for hybridization and bonding, so that unhexquadium should still behave chemically like a normal transition metal. Calculations predict that the 7d electrons of unhexquadium should participate very readily in chemical reactions, so that unhexquadium should be able to show stable +6 and +4 oxidation states in addition to the normal +2 state in aqueous solutions with strong ligands. Unhexquadium should thus be able to form compounds like Uhq(CO)4, Uhq(PF3)4 (both tetrahedral), and Uhq(CN)2−
2 (linear), which is very different behavior from that of lead, which unhexquadium would be a heavier homologue of if not for relativistic effects. Nevertheless, the divalent state would be the main one in aqueous solution, and unhexquadium(II) should behave more similarly to lead than unhexquadium(IV) and unhexquadium(VI).[33][34]

text: Unhexquadium should be a soft metal like mercury, and metallic unhexquadium should have a high melting point as it is predicted to bond covalently. It is also expected to be a soft Lewis acid and have Ahrlands softness parameter close to 4 eV. It should also have some similarities to oganesson as well as to the other group 12 elements.[33] Unhexquadium should be at most moderately reactive, having a first ionization energy that should be around 685 kJ/mol, comparable to that of molybdenum.[34][37] Due to the lanthanide, actinide, and superactinide contractions, unhexquadium should have a metallic radius of only 158 pm, very close to that of the much lighter magnesium, despite its being expected to have an atomic weight of around 474 u, about 19.5 times as much as that of magnesium.[37] This small radius and high weight cause it to be expected to have an extremely high density of around 46 g·cm−3, over twice that of osmium, currently the most dense element known, at 22.61 g·cm−3; unhexquadium should be the second most dense element in the first 9 periods of the periodic table, with only its neighbour unhextrium (element 163) being more dense (at 47 g·cm−3).[37] Metallic unhexquadium should be quite stable, as the 8s and 8p1/2 electrons are very deeply buried in the electron core and only the 7d electrons are available for bonding. Metallic unhexquadium should have a very large cohesive energy due to its covalent bonds, most probably resulting in a high melting point.[34]

text: Theoretical interest in the chemistry of unhexquadium is largely motivated by theoretical predictions that it, especially the isotope 482Uhq (with 164 protons and 318 neutrons), would be at the center of a hypothetical second island of stability (the first being centered around 306Ubb, with 122 protons and 184 neutrons).[38][39][40]

text: History[edit]

text: The elements of group 12 have been found throughout history, being used since ancient times to being discovered in laboratories. The group itself has not acquired a trivial name, but it has been called group IIB in the past.

text: Zinc[edit]

text: Zinc has been found being used in impure forms in ancient times as well as in alloys such as brass that have been found to be over 2000 years old.[41][42] Zinc was distinctly recognized as a metal under the designation of Fasada in the medical Lexicon ascribed to the Hindu king Madanapala (of Taka dynasty) and written about the year 1374.[43] The metal was also of use to alchemists.[44] The name of the metal was first documented in the 16th century,[45][46] and is probably derived from the German zinke for the needle-like appearance of metallic crystals.[47]

text: The isolation of metallic zinc in the West may have been achieved independently by several people in the 17th century.[48] German chemist Andreas Marggraf is usually given credit for discovering pure metallic zinc in a 1746 experiment by heating a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal.[49] Experiments on frogs by the Italian doctor Luigi Galvani in 1780 with brass paved the way for the discovery of electrical batteries, galvanization and cathodic protection.[50][51] In 1880, Galvani's friend, Alessandro Volta, invented the Voltaic pile.[50] The biological importance of zinc was not discovered until 1940 when carbonic anhydrase, an enzyme that scrubs carbon dioxide from blood, was shown to have zinc in its active site.[52]

text: Cadmium[edit]

text: In 1817, cadmium was discovered in Germany as an impurity in zinc carbonate minerals (calamine) by Friedrich Stromeyer and Karl Samuel Leberecht Hermann.[53] It was named after the Latin cadmia for "calamine", a cadmium-bearing mixture of minerals, which was in turn named after the Greek mythological character, Κάδμος Cadmus, the founder of Thebes.[54] Stromeyer eventually isolated cadmium metal by roasting and reduction of the sulfide.[55][56][57]

text: In 1927, the International Conference on Weights and Measures redefined the meter in terms of a red cadmium spectral line (1 m = 1,553,164.13 wavelengths).[58] This definition has since been changed (see krypton). At the same time, the International Prototype Meter was used as standard for the length of a meter until 1960,[59] when at the General Conference on Weights and Measures the meter was defined in terms of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in vacuum.[60]

text: Mercury[edit]

text: Mercury has been found in Egyptian tombs which have been dated back to 1500 BC,[61] where mercury was used in cosmetics. It was also used by the ancient Chinese who believed it would improve and prolong health.[62] By 500 BC mercury was used to make amalgams (Medieval Latin amalgama, "alloy of mercury") with other metals.[63] Alchemists thought of mercury as the First Matter from which all metals were formed. They believed that different metals could be produced by varying the quality and quantity of sulfur contained within the mercury. The purest of these was gold, and mercury was called for in attempts at the transmutation of base (or impure) metals into gold, which was the goal of many alchemists.[64]

text: Hg is the modern chemical symbol for mercury. It comes from hydrargyrum, a Latinized form of the Greek word Ύδραργυρος (hydrargyros), which is a compound word meaning "water-silver" (hydr- = water, argyros = silver) — since it is liquid like water and shiny like silver. The element was named after the Roman god Mercury, known for speed and mobility. It is associated with the planet Mercury; the astrological symbol for the planet is also one of the alchemical symbols for the metal.[65] Mercury is the only metal for which the alchemical planetary name became the common name.[64]

text: Copernicium[edit]

text: The heaviest known group 12 element, copernicium, was first created on February 9, 1996, at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, by Sigurd Hofmann, Victor Ninov et al.[66] It was then officially named by the International Union of Pure and Applied Chemistry (IUPAC) after Nicolaus Copernicus on February 19, 2010, the 537th anniversary of Copernicus' birth.[67]

text: Occurrence[edit]

text: Like in most other d-block groups, the abundance in Earth's crust of group 12 elements decreases with higher atomic number. Zinc is with 65 parts per million (ppm) the most abundant in the group while cadmium with 0.1 ppm and mercury with 0.08 ppm are orders of magnitude less abundant.[68] Copernicium, as a synthetic element with a half-life of a few minutes, may only be present in the laboratories where it was produced.

text: Group 12 metals are chalcophiles, meaning the elements have low affinities for oxides and prefer to bond with sulfides. Chalcophiles formed as the crust solidified under the reducing conditions of the early Earth's atmosphere.[69] The commercially most important minerals of group 12 elements are sulfide minerals.[23] Sphalerite, which is a form of zinc sulfide, is the most heavily mined zinc-containing ore because its concentrate contains 60–62% zinc.[13] No significant deposits of cadmium-containing ores are known. Greenockite (CdS), the only cadmium mineral of importance, is nearly always associated with sphalerite (ZnS). This association is caused by the geochemical similarity between zinc and cadmium which makes geological separation unlikely. As a consequence, cadmium is produced mainly as a byproduct from mining, smelting, and refining sulfidic ores of zinc, and, to a lesser degree, lead and copper.[70][71] One place where metallic cadmium can be found is the Vilyuy River basin in Siberia.[72] Although mercury is an extremely rare element in the Earth's crust,[73] because it does not blend geochemically with those elements that constitute the majority of the crustal mass, mercury ores can be highly concentrated considering the element's abundance in ordinary rock. The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury (12,000 times average crustal abundance). It is found either as a native metal (rare) or in cinnabar (HgS), corderoite, livingstonite and other minerals, with cinnabar being the most common ore.[74]

text: While mercury and zinc minerals are found in large enough quantities to be mined, cadmium is too similar to zinc and therefore is always present in small quantities in zinc ores from where it is recovered. Identified world zinc resources total about 1.9 billion tonnes.[75] Large deposits are in Australia, Canada and the United States with the largest reserves in Iran.[69][76][77] At the current rate of consumption, these reserves are estimated to be depleted sometime between 2027 and 2055.[78][79] About 346 million tonnes have been extracted throughout history to 2002, and one estimate found that about 109 million tonnes of that remains in use.[80] In 2005, China was the top producer of mercury with almost two-thirds global share followed by Kyrgyzstan.[81] Several other countries are believed to have unrecorded production of mercury from copper electrowinning processes and by recovery from effluents. Because of the high toxicity of mercury, both the mining of cinnabar and refining for mercury are hazardous and historic causes of mercury poisoning.[82]

text: Production[edit]

text: Zinc is the fourth most common metal in use, trailing only iron, aluminium, and copper with an annual production of about 10 million tonnes.[83] Worldwide, 95% of the zinc is mined from sulfidic ore deposits, in which sphalerite (ZnS) is nearly always mixed with the sulfides of copper, lead and iron. Zinc metal is produced using extractive metallurgy.[84] Roasting converts the zinc sulfide concentrate produced during processing to zinc oxide:[85] For further processing two basic methods are used: pyrometallurgy or electrowinning. Pyrometallurgy processing reduces zinc oxide with carbon or carbon monoxide at 950 °C (1,740 °F) into the metal, which is distilled as zinc vapor.[86] The zinc vapor is collected in a condenser.[85] Electrowinning processing leaches zinc from the ore concentrate by sulfuric acid:[87] After this step electrolysis is used to produce zinc metal.[85]

text: Cadmium is a common impurity in zinc ores, and it is most isolated during the production of zinc. Some zinc ores concentrates from sulfidic zinc ores contain up to 1.4% of cadmium.[88] Cadmium is isolated from the zinc produced from the flue dust by vacuum distillation if the zinc is smelted, or cadmium sulfate is precipitated out of the electrolysis solution.[89]

text: The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury, with cinnabar (HgS) being the most common ore in the deposits.[90] Mercury is extracted by heating cinnabar in a current of air and condensing the vapor.[91]

text: Super-heavy elements such as copernicium are produced by bombarding lighter elements in particle accelerators that induces fusion reactions. Whereas most of the isotopes of copernicium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers.[92] The first fusion reaction to produce copernicium was performed by GSI in 1996, who reported the detection of two decay chains of copernicium-277.[66]

text: In total, approximately 75 atoms of copernicium have been prepared using various nuclear reactions.

text: Applications[edit]

text: Due to the physical similarities which they share, the group 12 elements can be found in many common situations. Zinc and cadmium are commonly used as anti-corrosion (galvanization) agents[2] as they will attract all local oxidation until they completely corrode.[93] These protective coatings can be applied to other metals through by hot-dip galvanizing a substance into the molten form of the metal,[94] or through the process of electroplating which may be passivated by the use of chromate salts.[95] Group 12 elements are also used in electrochemistry as they may act as an alternative to the standard hydrogen electrode in addition to being a secondary reference electrode.[96]

text: In the US, zinc is used predominantly for galvanizing (55%) and for brass, bronze and other alloys (37%).[97] The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe.[98] Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.[98][note 4] Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion.[99][100] Zinc is also used as an anode material for batteries such as in zinc–carbon batteries[101][102] or zinc-air battery/fuel cells.[103][104][105] A widely used alloy which contains zinc is brass, in which copper is alloyed with anywhere from 3% to 45% zinc, depending upon the type of brass.[98] Brass is generally more ductile and stronger than copper and has superior corrosion resistance.[98] These properties make it useful in communication equipment, hardware, musical instruments, and water valves.[98] Other widely used alloys that contain zinc include nickel silver, typewriter metal, soft and aluminium solder, and commercial bronze.[9] Alloys of primarily zinc with small amounts of copper, aluminium, and magnesium are useful in die casting as well as spin casting, especially in the automotive, electrical, and hardware industries.[9] These alloys are marketed under the name Zamak.[106] Roughly one quarter of all zinc output, in the United States (2009), is consumed in the form of zinc compounds, a variety of which are used industrially.[97]

text: Cadmium has many common industrial uses as it is a key component in battery production, is present in cadmium pigments,[107] coatings,[95] and is commonly used in electroplating.[20] In 2009, 86% of cadmium was used in batteries, predominantly in rechargeable nickel-cadmium batteries. The European Union banned the use of cadmium in electronics in 2004 with several exceptions but reduced the allowed content of cadmium in electronics to 0.002%.[108] Cadmium electroplating, consuming 6% of the global production, can be found in the aircraft industry due to the ability to resist corrosion when applied to steel components.[20]

text: Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It is used in some thermometers, especially ones which are used to measure high temperatures. A still increasing amount is used as gaseous mercury in fluorescent lamps,[109] while most of the other applications are slowly phased out due to health and safety regulations,[110] and is in some applications replaced with less toxic but considerably more expensive Galinstan alloy.[111] Mercury and its compounds have been used in medicine, although they are much less common today than they once were, now that the toxic effects of mercury and its compounds are more widely understood.[112] It is still used as an ingredient in dental amalgams. In the late 20th century the largest use of mercury[113][114] was in the mercury cell process (also called the Castner-Kellner process) in the production of chlorine and caustic soda.[115]

text: Biological role and toxicity[edit]

text: The group 12 elements have multiple effects on biological organisms as cadmium and mercury are toxic while zinc is required by most plants and animals in trace amounts.

text: Zinc is an essential trace element, necessary for plants,[116] animals,[117] and microorganisms.[118] It is "typically the second most abundant transition metal in organisms" after iron and it is the only metal which appears in all enzyme classes.[116] There are 2–4 grams of zinc[119] distributed throughout the human body,[120] and it plays "ubiquitous biological roles".[121] A 2006 study estimated that about 10% of human proteins (2800) potentially bind zinc, in addition to hundreds which transport and traffic zinc.[116] In the U.S., the Recommended Dietary Allowance (RDA) is 8 mg/day for women and 11 mg/day for men.[122] Harmful excessive supplementation may be a problem and should probably not exceed 20 mg/day in healthy people,[123] although the U.S. National Research Council set a Tolerable Upper Intake of 40 mg/day.[124]

text: Mercury and cadmium are toxic and may cause environmental damage if they enter rivers or rain water. This may result in contaminated crops[125] as well as the bioaccumulation of mercury in a food chain leading to an increase in illnesses caused by mercury and cadmium poisoning.[126]

text: Notes[edit]

text:
^ Jump up to: a b See list of oxidation states of the elements. Oxidation states in bold are common.
Jump up ^ The color of the flame test of pure radium has never been observed; the crimson red color is an extrapolation from the flame test color of its compounds.[31]
Jump up ^ Sometimes reported as white.[29]
Jump up ^ Electric current will naturally flow between zinc and steel but in some circumstances inert anodes are used with an external DC source.

tag: ol


document_title: Nicky, Ricky, Dicky & Dawn

question_text: who plays dawn in nicky ricky dicky and dawn

text: Nicky, Ricky, Dicky & Dawn

text: Premise[edit]

text: The series focuses on quadruplets Nicky, Ricky, Dicky, and Dawn Harper, 10 years old at the start of the series,[1] who have nothing in common and often fight, but must work together to solve everyday situations.

text: Episodes[edit]

text: SeasonEpisodesOriginally airedFirst airedLast aired120September 13, 2014 (2014-09-13)March 24, 2015 (2015-03-24)225May 23, 2015 (2015-05-23)August 6, 2016 (2016-08-06)323January 7, 2017 (2017-01-07)August 5, 2017 (2017-08-05)414January 6, 2018 (2018-01-06)August 4, 2018 (2018-08-04)

text: Cast and characters[edit]

text:
Brian Stepanek as Tom, the father of the quadruplets. It is a running gag in the series that he cares more about his possessions than his children, but he loves his family and is a kid at heart.
Allison Munn as Anne, the mother of the quadruplets who usually gets caught up in Tom's new obsessions.
Aidan Gallagher as Nicky, the youngest of the quadruplets. He is shown to be quite comedic, quirky, and easily confused.
Casey Simpson as Ricky, is the second oldest of the quadruplets. He is the smart one of the group, always seen carrying a book or doing his homework. He is also a neat freak and a bit of a goody two-shoes, though he occasionally tries to prove to Dawn and his brothers that he can bend rules as well.
Mace Coronel as Dicky, the third oldest and easy-going quadruplet who cares a great deal about his appearance. He always takes the easy way out. He ships himself to Australia in "Quadcodile Dundee".
Lizzy Greene as Dawn, the oldest of the quadruplets. Although she's always seen bothering her brothers, she does care about them deeply. There is a consistent rivalry for the leader spot of the quads between her and Ricky.
Gabrielle Elyse as Josie, a worker at Tom's sporting shop and babysitter for Nicky, Ricky, Dicky and Dawn. She only appears in the first season.
Kyla-Drew Simmons as Mae, the quads' friend and Dawn's best friend. She once called herself "the fifth quad". In the first two seasons, she is a recurring character, but she is promoted to a main character in the third season.

tag: ul

text: Production[edit]

text: The series was originally picked up for 13 episodes on March 13, 2014, but was later increased to 20 episodes.[2] The series premiered on September 13, 2014. On November 18, 2014, the series was renewed for a second season.[3] The second season premiered on May 23, 2015. On February 9, 2016, Nickelodeon renewed Nicky, Ricky, Dicky & Dawn for a third season of 14 episodes. It was also confirmed that Matt Fleckenstein would step down as show runner.[4] Actress Lizzy Greene announced on her Twitter account that production for season three started on April 26, 2016.[5] The third season premiered on January 7, 2017. The series was renewed for a fourth season and had its episode order for the third season increased from 14 to 24 by Nickelodeon on March 20, 2017.[6] On October 4, 2017, it was announced that Mace Coronel would be leaving both Nicky, Ricky, Dicky & Dawn, about five episodes before the end of the fourth season, and Nickelodeon.[7] On November 15, 2017, Nickelodeon announced that the fourth season would be the last.[8]

text: Reception[edit]

text: Ratings[edit]

text:
Season

Episodes

First aired

Last aired
Avg. viewers(millions)

Date

Viewers(millions)

Date

Viewers(millions)

1

20

September 13, 2014 (2014-09-13)

1.60[9]

March 24, 2015 (2015-03-24)

1.75[10]
1.75

2

25

May 23, 2015 (2015-05-23)

1.11[11]

August 6, 2016 (2016-08-06)

1.31[12]
1.46

3

23

January 7, 2017 (2017-01-07)

1.58[13]

August 5, 2017 (2017-08-05)

2.00[14]
1.47

4

14

January 6, 2018 (2018-01-06)

1.08[15]

August 4, 2018 (2018-08-04)

0.84[16]
0.95

text: Awards and nominations[edit]

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2017) (Learn how and when to remove this template message)

text:
Year

Award

Category

Result

Refs

2015

Nickelodeon Kids' Choice Awards

Favorite TV Show

Nominated

[17][18]

2017

Nickelodeon Kids' Choice Awards

Favorite TV Show – Kids' Show

Nominated

[19]