document_title: Chinese units of measurement

question_text: who introduced a standardized system of weights and measures in china

text: Chinese units of measurement

text: History[edit]

text:
History of science and
technology in China

Inventions

Four Great Inventions

Discoveries

By subject

Mathematics
Astronomy
Calendar
Units of measurement
Cartography
Geography
Printing
Ceramics
Metallurgy
Coinage
Chinese Alchemy
Traditional medicine

herbology

Agriculture

Sericulture

Silk industry
Architecture

Classic gardens
Bridges

Transport

Navigation

Military

Navy

By era

Han
Tang
Song
People's Republic

Agriculture

v
t
e

text: According to the Liji, the legendary Yellow Emperor created the first measurement units. The Xiao Erya and the Kongzi Jiayu state that length units were derived from the human body. According to the Records of the Grand Historian, these human body units caused inconsistency, and Yu the Great, another legendary figure, unified the length measurements. Rulers with decimal units have been unearthed from Shang Dynasty tombs.

text: In the Zhou Dynasty, the king conferred nobles with powers of the state and the measurement units began to be inconsistent from state to state. After the Warring States period, Qin Shi Huang unified China, and later standardized measurement units. In the Han Dynasty, these measurements were still being used, and were documented systematically in the Book of Han.

text: Astronomical instruments show little change of the length of chi in the following centuries, since the calendar needed to be consistent. It was not until the introduction of decimal units in the Ming Dynasty that the traditional system was revised.

text: Republican Era[edit]

text: On 7 January 1915, the Beiyang Government promulgated a measurement law to use not only metric system as the standard but also a set of Chinese-style measurement.[1] On 16 February 1929, the Nationalist Government adopted and promulgated The Weights and Measures Act[2] to adopt the metric system as the official standard and to limit the newer Chinese units of measurement (Chinese: 市用制; pinyin: shìyòngzhì; literally: "market-use system") to private sales and trade in Article 11, effective on 1 January 1930.[3]

text: People's Republic of China[edit]

text: The Government of the People's Republic of China continued using the market system along with metric system, as decreed by the State Council of the People's Republic of China on 25 June 1959, but 1 catty being 500 grams, would become divided into 10 (new) taels, instead of 16 (old) taels, to be converted from province to province, while exempting Chinese prescription drugs from the conversion to prevent errors.[4]

text: On 27 February 1984, the State Council of the People's Republic of China decreed the market system to remain acceptable till the end of 1990 and ordered the transition to the national legal measures by that time, but farmland measures would be exempt from this mandatory metrication until further investigation and study.[5]

text: Hong Kong[edit]

text: In 1976 the Hong Kong Metrication Ordinance allowed a gradual replacement of the system in favor of the International System of Units (SI) metric system.[6] The Weights and Measures Ordinance defines the metric, Imperial, and Chinese units.[7] As of 2012, all three systems are legal for trade and are in widespread use.

text: Macau[edit]

text: On 24 August 1992, Macau published Law No. 14/92/M to order that Chinese units of measurement similar to those used in Hong Kong, Imperial units, and United States customary units would be permissible for five years since the effective date of the Law, 1 January 1993, on the condition of indicating the corresponding SI values, then for three more years thereafter, Chinese, Imperial, and US units would be permissible as secondary to the SI.[8]

text: Ancient Chinese units[edit]

text: Length[edit]

text: Traditional units of length include the chi (尺), bu (步), and li (里). The precise length of these units, and the ratios between these units, has varied over time. 1 bu has consisted of either 5 or 6 chi, while 1 li has consisted of 300 or 360 bu.

text:
Length in metre[9]

dynasty
chi
bu
li

= 5 chi
= 6 chi
= 300 bu
= 360 bu

Shang
0.1675

1.0050
301.50

0.1690

1.0140
304.20

Zhou
0.1990

1.1940
358.20

Eastern Zhou
0.2200

1.3200
396.00

0.2270

1.3620
408.60

0.2310

1.3860
415.80

Qin
0.2310

1.3860
415.80[10][11]

Han
0.2310

1.3860
415.80[12] 415.80[10][11]

600 CE
0.2550

1.5300
459.00

Tang
0.2465
1.2325

369.75
443.70

0.2955
1.4775

443.25
531.90

Song
0.2700
1.3500

405.00
486.00

Northern Song
0.3080
1.5400

462.00
554.40

Ming
0.3008–0.3190
1.5040–1.5950

451.20–478.50
541.44–574.20

Qing
0.3080–0.3352
1.5400–1.6760

462.00–503.89
554.40–603.46

text: Modern Chinese units[edit]

text: All "metric values" given in the tables are exact unless otherwise specified by the approximation sign '~'.

text: Certain units are also listed at List of Chinese classifiers → Measurement units.

text: Length[edit]

text: Chinese length units promulgated in 1915[edit]

text:
Table of Chinese length units promulgated in 1915[1]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

háo
毫
 1⁄10 000
32 µm
0.00126 in

lí
釐 (T) or 厘 (S)
 1⁄1000
0.32 mm
0.0126 in

fēn
分
 1⁄100
3.2 mm
0.126 in

cùn
寸
 1⁄10
32 mm
1.26 in
Chinese inch

chǐ
尺
1
0.32 m
12.6 in
Chinese foot

bù
步
5
1.6 m
5.2 ft
Chinese pace

zhàng
丈
10
3.2 m
3.50 yd

yǐn
引
100
32 m
35.0 yd

lǐ
里
1800
576 m
630 yd
this li is not the small li above,
which has a different character and tone

text: Chinese length units effective in 1930[edit]

text:
Table of Chinese length units effective in 1930[3]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

háo
毫
 1⁄10 000
 33 1⁄3 µm
0.00131 in

lí
釐 (T) or 厘 (S)
 1⁄1000
 1⁄3 mm
0.0131 in

fēn
市分
 1⁄100
 3 1⁄3 mm
0.1312 in

cùn
市寸
 1⁄10
 3 1⁄3 cm
1.312 in
Chinese inch

chǐ
市尺
1
 33 1⁄3 cm
13.12 in
Chinese foot

zhàng
市丈
10
 3 1⁄3 m
3.645 yd

yǐn
引
100
 33 1⁄3 m
36.45 yd

lǐ
市里
1500
500 m
546.8 yd
this li is not the small li above,
which has a different character and tone

text: Metric length units[edit]

text: The Chinese word for metre is 米 mǐ; this can take the Chinese standard SI prefixes (for "kilo-", "centi-", etc.). A kilometre, however, may also be called 公里 gōnglǐ, i.e. a metric lǐ.

text: In the engineering field, traditional units are rounded up to metric units.For example, the Chinese word 丝 sī is used to express 0.01 mm.

text:
Table of Chinese length units in engineering

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

hū
忽
 1⁄1 000 000
1 µm

Authorized name: 微米

sī
丝
 1⁄100 000
10 µm

Authorized name: 忽米

háo
毫
 1⁄10 000
100 µm

Authorized name: 丝米

lí
釐 (T) or 厘 (S)
 1⁄1000
1 mm

Authorized name: 毫米

fēn
公分
 1⁄100
10 mm

Authorized name: 厘米

cùn
公寸
 1⁄10
100 mm

Authorized name: 分米

chǐ
公尺
1
1 m

Authorized name: 米

lǐ
公里
1000
1000 m

this li is not the small li above,
which has a different character and tone

text: Hong Kong and Macau length units[edit]

text:
Table of Chinese length units in Hong Kong[7] and Macau[8]

English
Jyutping
Character
Portuguese
Relative value
Metric value
Imperial value
Notes

fan
fan1
分
condorim
 1⁄100
3.71475 mm
0.1463 in

tsun
cyun3
寸
ponto
 1⁄10
3.71475 cm
1.463 in

chek
cek3
尺
côvado
1
37.1475 cm
1.219 ft
Hong Kong and Macau foot

text: Area[edit]

text: Chinese area units promulgated in 1915[edit]

text:
Table of Chinese area units promulgated in 1915[1]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

háo
毫
 1⁄1000
0.6144 m2
0.7348 sq yd

lí
釐 (T) or 厘 (S)
 1⁄100
6.144 m2
7.348 sq yd

fēn
分
 1⁄10
61.44 m2
73.48 sq yd
10 li

mǔ
畝 (T) or 亩 (S)
1
614.4 m2
734.82 sq yd
10 fen, or 60 square zhang

qǐng
頃 (T) or 顷 (S)
100
6.144 ha
15.18 acre
100 mǔ

text:
Table of Chinese square units effective in 1915[1]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

fāng cùn
方寸
 1⁄100
10.24 cm2
1.587 sq in
square cun

fāng chǐ
方尺
1
0.1024 m2
1.102 sq ft
square chi

fāng zhàng
方丈
100
10.24 m2
110.2 sq ft
square zhang

text: Chinese area units effective in 1930[edit]

text:
Table of Chinese area units effective in 1930[3]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

háo
毫
 1⁄1000
 2⁄3 m2
7.18 sq ft

lí
釐 (T) or 厘 (S)
 1⁄100
 6 2⁄3 m2
7.973 sq yd

fēn
市分
 1⁄10
 66 2⁄3 m2
79.73 sq yd
10 li

mǔ
畝 (T) or 亩 (S)
1
 666 2⁄3 m2
797.3 sq yd
0.1647 acre
10 fen
60 square zhang

qǐng
頃 (T) or 顷 (S)
100
 6 2⁄3 ha
16.47 acre
10 shí or 100 mǔ

text:
Table of Chinese square units effective in 1930[3]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

fāng cùn
方寸
 1⁄100
 11 1⁄9 cm2
1.722 sq in
square cun

fāng chǐ
方尺
1
 1⁄9 m2
172.2 sq in
1.196 sq ft
square chi

fāng zhàng
方丈
100
 11 1⁄9 m2
119.6 sq ft
13.29 sq yd
square zhang

text: Metric and other area units[edit]

text: Metric and other standard length units can be squared by the addition of the prefix 平方 píngfāng. For example, a square kilometre is 平方公里 píngfāng gōnglǐ.

text: Macau area units[edit]

text:
Table of Chinese area units in Macau[8]

Jyutping
Character
Portuguese
Relative value
Metric value
Imperial value
Notes

cek3
尺
côvado
 1⁄6000
0.1269 m2
1.366 sq ft

pou3
鋪

 1⁄240
3.1725 m2
34.15 sq ft
3.794 sq yd

zoeng6
丈
braça
 1⁄60
12.69 m2
136.6 sq ft
15.18 sq yd

fan1
分
condorim
 1⁄10
76.14 m2
91.06 sq yd

mau5
畝 (T) or 亩 (S)
maz
1
761.4 m2
910.6 sq yd

text: Volume[edit]

text: These units are used to measure cereal grains, among other things. In imperial times, the physical standard for these was the jialiang.

text: Chinese volume units promulgated in 1915[edit]

text:
Table of Chinese volume units effective in 1915[1]

Pinyin
Character
Relative value
Metric value
US value
Imperial value
Notes

sháo
勺
 1⁄100
10.354688 ml
0.3501 fl oz
0.3644 fl oz

gě
合
 1⁄10
103.54688 ml
3.501 fl oz
3.644 fl oz

shēng
升
1
1.0354688 l
2.188 pt
1.822 pt

dǒu
斗
10
10.354688 l
2.735 gal
2.278 gal

hú
斛
50
51.77344 l
13.68 gal
11.39 gal

dàn
石
100
103.54688 l
27.35 gal
22.78 gal

text: Chinese volume units effective in 1930[edit]

text:
Table of Chinese volume units effective in 1930[3]

Pinyin
Character
Relative value
Metric value
US value
Imperial value
Notes

cuō
撮
 1⁄1000
1 ml
0.0338 fl oz
0.0352 fl oz

sháo
勺
 1⁄100
10 ml
0.3381 fl oz
0.3520 fl oz

gě
合
 1⁄10
100 ml
3.381 fl oz
3.520 fl oz

shēng
市升
1
1 l
2.113 pt
1.760 pt

dǒu
市斗
10
10 l
21.13 pt
2.64 gal
17.60 pt
2.20 gal

dàn
市石
100
100 l
26.41 gal
22.0 gal

text: Metric volume units[edit]

text: In the case of volume, the market and metric shēng coincide, being equal to one litre as shown in the table. The Chinese standard SI prefixes (for "milli-", "centi-", etc.) may be added to this word shēng.

text: Units of volume can also be obtained from any standard unit of length using the prefix 立方 lìfāng ("cubic"), as in 立方米 lìfāng mǐ for a cubic metre.

text: Macau volume units[edit]

text:
Table of Chinese volume units in Macau[8]

Jyutping
Character
Portuguese
Relative value
Metric value
Imperial value
Notes

cyut3
撮

1
1.031 l

gam1 dak6
甘特

10
10.31 l

sek6
石

100
103.1 l

text: Mass[edit]

text: These units are used to measure the mass of objects. They are also famous for measuring monetary objects such as gold and silver.

text: Chinese mass units promulgated in 1915[edit]

text:
Table of Chinese mass units promulgated in 1915[1]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

háo
毫
 1⁄10 000
3.7301 mg
0.0001316 oz

lí
釐
 1⁄1000
37.301 mg
0.001316 oz
cash

fēn
分
 1⁄100
373.01 mg
0.01316 oz
candareen

qián
錢
 1⁄10
3.7301 g
0.1316 oz
mace

liǎng
兩
1
37.301 g
1.316 oz
tael or Chinese ounce

jīn
斤
16
596.816 g
1.316 lb
catty or Chinese pound

text: Mass units in the Republic of China since 1930[edit]

text:
Table of mass units in the Republic of China since 1930[3]

Pinyin
Character
Relative value
Metric value
Imperial value
Notes

sī
絲
 1⁄1 600 000
312.5 µg
0.00001102 oz

háo
毫
 1⁄160 000
3.125 mg
0.0001102 oz

lí
市釐
 1⁄16 000
31.25 mg
0.001102 oz
cash

fēn
市分
 1⁄1600
312.5 mg
0.01102 oz
candareen

qián
市錢
 1⁄160
3.125 g
0.1102 oz
mace

liǎng
市兩
 1⁄16
31.25 g
1.102 oz
tael or Chinese ounce

jīn
市斤
1
500 g
1.102 lb
catty or Chinese pound

dàn
擔 / 担
100
50 kg
110.2 lb
picul or Chinese hundredweight

text: Mass units in the People's Republic of China since 1959[edit]

text:
Table of mass units in the People's Republic of China since 1959[4]

Pinyin
Character[13]
Relative value
Metric value
Imperial value
Notes

lí
市厘
 1⁄10 000
50 mg
0.001764 oz
cash

fēn
市分
 1⁄1000
500 mg
0.01764 oz
candareen

qián
市钱
 1⁄100
5 g
0.1764 oz
mace

liǎng
市两
 1⁄10
50 g
1.764 oz
tael or Chinese ounce

jīn
市斤
1
500 g
1.102 lb
catty or Chinese pound
formerly 16 liang = 1 jin

dàn
市担 / 擔
100
50 kg
110.2 lb
picul or Chinese hundredweight

text: Metric mass units[edit]

text: The Chinese word for gram is 克 kè; this can take the Chinese standard SI prefixes (for "milli-", "deca-", etc.). A kilogram, however, is commonly called 公斤 gōngjīn, i.e. a metric jīn.

text: Hong Kong and Macau mass units[edit]

text:
Table of Chinese mass units in Hong Kong[7] and Macau[8]

English
Jyutping
Character
Portuguese
Relative value
Metric value
Imperial value
Notes

lei4
厘
liz
 1⁄16 000
37.79931 mg
0.02133 dr
Not defined in Hong Kong. Macanese definition may not be correct when dividing catty.

candareen (fan)
fan1
分
condorim
 1⁄1600
377.9936375 mg
0.2133 dr
Macanese definition of 377.9931 mg may not be correct when dividing catty.

mace (tsin)
cin4
錢
maz
 1⁄160
3.779936375 g
2.1333 dr
Macanese definition of 3.779931 g may not be correct when dividing catty.

tael (leung)
loeng2
兩
tael
 1⁄16
37.79936375 g
1.3333 oz
Macanese definition of 37.79931 g may not be correct when dividing catty.

catty (kan)
gan1
斤
cate
1
604.78982 g
1.3333 lb
Hong Kong and Macau share the definition.

picul (tam)
daam3
担 / 擔
pico
100
60.478982 kg
133.3333 lb
Hong Kong and Macau share the definition.

text: Hong Kong troy units[edit]

text: These are used for trading precious metals such as gold and silver.

text:
Table of mass (Hong Kong troy) units[7]

English
Character
Relative value
Metric value
Imperial value
Notes

troy candareen
金衡分
 1⁄100
374.29 mg
0.096 drt

troy mace
金衡錢
 1⁄10
3.7429 g
0.96 drt

troy tael
金衡兩
1
37.429 g
1.2 ozt

text: Time[edit]

text:
Table of time units

Pinyin
Character
Relative value
Western value
Notes

tradition value
modern value
tradition value
modern value

miǎo
秒

144 milliseconds
1 second

fēn
分
100 hǎo
60 miǎo
14.4 seconds
1 minute

kè
刻
1 minor kè=10 fēn
15 fēn
2.4 minutes
15 minutes
kè was defined at  1⁄96,  1⁄108, or  1⁄120 day during the Liang dynasty, and established at  1⁄96 day after the Qing dynasty.

1 major kè=60 fēn
14.4 minutes

diǎn
点
100 fēn
60 fēn
24 minutes
1 hour

shí [14]
時 (T)
时 (S)
 8 1⁄3 kè
4 kè
2 hours
1 hour
the xiǎoshí(小時/小时) is currently used to express "hour" in order to avoid the ambiguity

(pre-Qin) 10 kè
2.4 hours

rì / tiān
日/天
12 shí
24 shí
24 hours

text: Historiography[edit]

text: As there were hundreds of unofficial measures in use, the bibliography is quite vast. The editions of Wu Chenglou's 1937 History of Chinese Measurement[15] were the usual standard up to the 1980s or so, but rely mostly on surviving literary accounts. Newer research has put more emphasis on archeological discoveries.[16] Qiu Guangming & Zhang Yanming's 2005 bilingual Concise History of Ancient Chinese Measures and Weights summarizes these findings.[17] A relatively recent and comprehensive bibliography, organized by period studied, has been compiled in 2012 by Cao & al.;[18] for a shorter list, see Wilkinson's year 2000 Chinese History.[16]


document_title: List of Wimbledon ladies' singles champions

question_text: who is the defending ladies' singles champion

question_tokens: who is the defending ladies ' singles champion

root

text: History[edit]

text: Wimbledon has historically been played in the last week of June and the first week of July (though changed to the first two weeks of July in 2017), and has been chronologically the third of the four Grand Slam tournaments of the tennis season since 1987.[2] The event was not held from 1915 to 1918 because of World War I and again from 1940 to 1945 because of World War II.[4]

tag: p

text: The Ladies' Singles' rules have undergone several changes since the first edition. From 1886 until 1921, the event started with a knockout phase, the All Comers' Singles, whose winner then faced the defending champion in a challenge round. The All Comers' winner was automatically awarded the title six times (1887, 1891, 1895, 1907, 1908) in the absence of the previous year's champion. The challenge round system was abolished with the 1922 edition.[5] Since the first championships, all matches have been played at the best-of-three sets. Between 1877 and 1883, the winner of the next game at five games-all took the set in every match except the All Comers' final, and the challenge round, which were won with six games and a two games advantage. All sets were decided in two-game advantage format from 1884 to 1970.[5] The lingering death best-of-12 points tie-break was introduced in 1971 for the first two sets, played at eight games-all until 1978 and at six games-all since 1979.[5][6][7]

text: The Ladies' Singles champion receives a sterling silver salver commonly known as the "Venus Rosewater Dish", or simply the "Rosewater Dish". The salver, which is 18.75 inches (about 48 cm) in diameter, is decorated with figures from mythology.[8] New singles champions are traditionally elected honorary members of the AELTC by the club's committee.[c][9] In 2012, the Ladies' Singles winner received prize money of £1,150,000.[10]

text: These records include the Amateur Era only, Dorothea Lambert Chambers (1903–1904, 1906, 1910–1911, 1913–1914) holds the record for most titles, with seven, and Lottie Dod (1891–1893) and Suzanne Lenglen (1919–1921) holds the record for most consecutive wins in the Ladies' Singles during the challenge round era, with three victories each. The record for most consecutive and most wins post challenge round during the Amateur Era is Helen Wills Moody (1927–1930), with four straight wins, and Moody holds the record for most victories in this era with eight (1927–1930, 1932–1933, 1935, 1938).[4]

text: These records only include the Open Era, since the inclusion of the professional tennis players, Martina Navratilova (1978–1979, 1982–1987, 1990) holds the record for most victories with nine. Navratilova holds the record for most consecutive victories with six (1982–1987).[4]

text: This event has been won without the loss of a set, during the Open Era of Tennis, by the following players: Billie Jean King in 1968, 1972, 1973 and 1975, Margaret Court in 1970, Evonne Goolagong Cawley in 1971 and 1980, Chris Evert in 1974 and 1981, Martina Navratilova in 1979, 1983, 1984, 1986, 1987, and 1990, Steffi Graf in 1992 and 1996, Jana Novotná in 1998, Lindsay Davenport in 1999, Venus Williams in 2000, 2007 and 2008, Serena Williams in 2002, 2009, 2010, 2015 and 2016, Maria Sharapova in 2004, Petra Kvitová in 2011 and 2014 and Marion Bartoli in 2013.

text: Champions[edit]

text:
Regular competition

All Comers' winner, Challenge round winner ‡

Defending champion, Challenge round winner †

All Comers' winner, no Challenge round ◊

tag: table

text: Amateur Era[edit]

text:
Year[d]

Country

Champion

Country

Runner-up

Score in the final[4]

1884
 BRI[e]
Maud Watson
 BRI
Lillian Watson
6–8, 6–3, 6–3

1885
 BRI
Maud Watson
 BRI
Blanche Bingley
6–1, 7–5

1886
 BRI
Blanche Bingley ‡
 BRI
Maud Watson
6–3, 6–3

1887
 BRI
Lottie Dod ‡
 BRI
Blanche Bingley
6–2, 6–0

1888
 BRI
Lottie Dod †
 BRI
Blanche Hillyard
6–3, 6–3

1889
 BRI
Blanche Hillyard ◊
 BRI
Lena Rice
4–6, 8–6, 6–4

1890
 BRI
Lena Rice ◊
 BRI
May Jacks
6–4, 6–1

1891
 BRI
Lottie Dod ◊
 BRI
Blanche Hillyard
6–2, 6–1

1892
 BRI
Lottie Dod †
 BRI
Blanche Hillyard
6–1, 6–1

1893
 BRI
Lottie Dod †
 BRI
Blanche Hillyard
6–8, 6–1, 6–4

1894
 BRI
Blanche Hillyard ◊
 BRI
Edith Austin
6–1, 6–1

1895
 BRI
Charlotte Cooper ◊
 BRI
Helen Jackson
7–5, 8–6

1896
 BRI
Charlotte Cooper †
 BRI
Alice Pickering
6–2, 6–3

1897
 BRI
Blanche Hillyard ‡
 BRI
Charlotte Cooper
5–7, 7–5, 6–2

1898
 BRI
Charlotte Cooper ◊
 BRI
Louisa Martin
6–4, 6–4

1899
 BRI
Blanche Hillyard ‡
 BRI
Charlotte Cooper
6–2, 6–3

1900
 BRI
Blanche Hillyard †
 BRI
Charlotte Cooper
4–6, 6–4, 6–4

1901
 BRI
Charlotte Sterry ‡
 BRI
Blanche Hillyard
6–2, 6–2

1902
 BRI
Muriel Robb ‡
 BRI
Charlotte Sterry
7–5, 6–1

1903
 BRI
Dorothea Douglass ◊
 BRI
Ethel Larcombe
4–6, 6–4, 6–2

1904
 BRI
Dorothea Douglass †
 BRI
Charlotte Sterry
6–0, 6–3

1905
 USA
May Sutton ‡
 BRI
Dorothea Douglass
6–3, 6–4

1906
 BRI
Dorothea Douglass ‡
 USA
May Sutton
6–3, 9–7

1907
 USA
May Sutton ‡
 BRI
Dorothea Lambert Chambers
6–1, 6–4

1908
 BRI
Charlotte Sterry ◊
 BRI
Agnes Morton
6–4, 6–4

1909
 BRI
Dora Boothby ◊
 BRI
Agnes Morton
6–4, 4–6, 8–6

1910
 BRI
Dorothea Lambert Chambers ‡
 BRI
Dora Boothby
6–2, 6–2

1911
 BRI
Dorothea Lambert Chambers †
 BRI
Dora Boothby
6–0, 6–0

1912
 BRI
Ethel Larcombe ◊
 BRI
Charlotte Sterry
6–3, 6–1

1913
 BRI
Dorothea Lambert Chambers ◊
 BRI
Winifred McNair
6–0, 6–4

1914
 BRI
Dorothea Lambert Chambers †
 BRI
Ethel Larcombe
7–5, 6–4

1915
No competition (due to World War I)

1916

1917

1918

1919
 FRA
Suzanne Lenglen ‡
 BRI
Dorothea Lambert Chambers
10–8, 4–6, 9–7

1920
 FRA
Suzanne Lenglen †
 BRI
Dorothea Lambert Chambers
6–3, 6–0

1921
 FRA
Suzanne  Lenglen †
 USA
Elizabeth Ryan
6–2, 6–0

1922
 FRA
Suzanne Lenglen
 USA
Molla Mallory
6–2, 6–0

1923
 FRA
Suzanne  Lenglen
 GBR
Kitty McKane
6–2, 6–2

1924
 GBR
Kitty McKane
 USA
Helen Wills
4–6, 6–4, 6–4

1925
 FRA
Suzanne Lenglen
 GBR
Joan Fry
6–2, 6–0

1926
 GBR
Kitty Godfree
 ESP
Lilí Álvarez
6–2, 4–6, 6–3

1927
 USA
Helen Wills
 ESP
Lilí Álvarez
6–2, 6–4

1928
 USA
Helen Wills
 ESP
Lilí Álvarez
6–2, 6–3

1929
 USA
Helen Wills
 USA
Helen Jacobs
6–1, 6–2

1930
 USA
Helen Moody
 USA
Elizabeth Ryan
6–2, 6–2

1931
 GER
Cilly Aussem
 GER
Hilde Krahwinkel
6–2, 7–5

1932
 USA
Helen Moody
 USA
Helen Jacobs
6–3, 6–1

1933
 USA
Helen Moody
 GBR
Dorothy Round
6–4, 6–8, 6–3

1934
 GBR
Dorothy Round
 USA
Helen Jacobs
6–2, 5–7, 6–3

1935
 USA
Helen Moody
 USA
Helen Jacobs
6–3, 3–6, 7–5

1936
 USA
Helen Jacobs
 DEN
Hilde Sperling
6–2, 4–6, 7–5

1937
 GBR
Dorothy Round
 POL
Jadwiga Jędrzejowska
6–2, 2–6, 7–5

1938
 USA
Helen Moody
 USA
Helen Jacobs
6–4, 6–0

1939
 USA
Alice  Marble
 GBR
Kay Stammers
6–2, 6–0

1940
No competition (due to World War II)

1941

1942

1943

1944

1945

1946
 USA
Pauline Betz
 USA
Louise Brough
6–2, 6–4

1947
 USA
Margaret Osborne
 USA
Doris Hart
6–2, 6–4

1948
 USA
Louise Brough
 USA
Doris Hart
6–3, 8–6

1949
 USA
Louise Brough
 USA
Margaret duPont
10–8, 1–6, 10–8

1950
 USA
Louise Brough
 USA
Margaret duPont
6–1, 3–6, 6–1

1951
 USA
Doris Hart
 USA
Shirley Fry
6–1, 6–0

1952
 USA
Maureen Connolly
 USA
Louise Brough
7–5, 6–3

1953
 USA
Maureen Connolly
 USA
Doris Hart
8–6, 7–5

1954
 USA
Maureen Connolly
 USA
Louise Brough
6–2, 7–5

1955
 USA
Louise Brough
 USA
Beverly Fleitz
7–5, 8–6

1956
 USA
Shirley Fry
 GBR
Angela Buxton
6–3, 6–1

1957
 USA
Althea Gibson
 USA
Darlene Hard
6–3, 6–2

1958
 USA
Althea Gibson
 GBR
Angela Mortimer
8–6, 6–2

1959
 BRA
Maria Bueno
 USA
Darlene Hard
6–4, 6–3

1960
 BRA
Maria Bueno
 RSA
Sandra Reynolds
8–6, 6–0

1961
 GBR
Angela Mortimer
 GBR
Christine Truman
4–6, 6–4, 7–5

1962
 USA
Karen Susman
 TCH
Věra Suková
6–4, 6–4

1963
 AUS
Margaret Smith
 USA
Billie Jean Moffitt
6–3, 6–4

1964
 BRA
Maria Bueno
 AUS
Margaret Smith
6–4, 7–9, 6–3

1965
 AUS
Margaret Smith
 BRA
Maria Bueno
6–4, 7–5

1966
 USA
Billie Jean King
 BRA
Maria Bueno
6–3, 3–6, 6–1

1967
 USA
Billie Jean King
 GBR
Ann Jones
6–3, 6–4

text: Open Era[edit]

text:
Year[d]

Country

Champion

Country

Runner-up

Score in the final[4]

1968
 USA
Billie Jean King
 AUS
Judy Tegart
9–7, 7–5

1969
 GBR
Ann Jones
 USA
Billie Jean King
3–6, 6–3, 6–2

1970
 AUS
Margaret Court
 USA
Billie Jean King
14–12, 11–9

1971
 AUS
Evonne Goolagong
 AUS
Margaret Court
6–4, 6–1

1972
 USA
Billie Jean King
 AUS
Evonne Goolagong
6–3, 6–3

1973
 USA
Billie Jean King
 USA
Chris Evert
6–0, 7–5

1974
 USA
Chris Evert
 URS
Olga Morozova
6–0, 6–4

1975
 USA
Billie Jean King
 AUS
Evonne Goolagong Cawley
6–0, 6–1

1976
 USA
Chris Evert
 AUS
Evonne Goolagong Cawley
6–3, 4–6, 8–6

1977
 GBR
Virginia Wade
 NED
Betty Stöve
4–6, 6–3, 6–1

1978
 USA
Martina Navratilova[i][11]
 USA
Chris Evert
2–6, 6–4, 7–5

1979
 USA
Martina Navratilova
 USA
Chris Evert Lloyd
6–4, 6–4

1980
 AUS
Evonne Goolagong Cawley
 USA
Chris Evert Lloyd
6–1, 7–6(7–4)

1981
 USA
Chris Evert Lloyd
 TCH[h]
Hana Mandlíková
6–2, 6–2

1982
 USA
Martina Navratilova
 USA
Chris Evert Lloyd
6–1, 3–6, 6–2

1983
 USA
Martina Navratilova
 USA
Andrea Jaeger
6–0, 6–3

1984
 USA
Martina Navratilova
 USA
Chris Evert Lloyd
7–6(7–5), 6–2

1985
 USA
Martina Navratilova
 USA
Chris Evert Lloyd
4–6, 6–3, 6–2

1986
 USA
Martina Navratilova
 TCH
Hana Mandlíková
7–6(7–1), 6–3

1987
 USA
Martina Navratilova
 FRG[j]
Steffi Graf
7–5, 6–3

1988
 FRG[j]
Steffi Graf
 USA
Martina Navratilova
5–7, 6–2, 6–1

1989
 FRG
Steffi Graf
 USA
Martina Navratilova
6–2, 6–7(1–7), 6–1

1990
 USA
Martina Navratilova
 USA
Zina Garrison
6–4, 6–1

1991
 GER
Steffi Graf
 ARG
Gabriela Sabatini
6–4, 3–6, 8–6

1992
 GER
Steffi Graf
 YUG
Monica Seles
6–2, 6–1

1993
 GER
Steffi Graf
 CZE
Jana Novotná
7–6(8–6), 1–6, 6–4

1994
 ESP
Conchita Martínez
 USA
Martina Navratilova
6–4, 3–6, 6–3

1995
 GER
Steffi Graf
 ESP
Arantxa Sánchez Vicario
4–6, 6–1, 7–5

1996
 GER
Steffi Graf
 ESP
Arantxa Sánchez Vicario
6–3, 7–5

1997
  SUI
Martina Hingis
 CZE
Jana Novotná
2–6, 6–3, 6–3

1998
 CZE
Jana Novotná
 FRA
Nathalie Tauziat
6–4, 7–6(7–2)

1999
 USA
Lindsay Davenport
 GER
Steffi Graf
6–4, 7–5

2000
 USA
Venus Williams
 USA
Lindsay Davenport
6–3, 7–6(7–3)

2001
 USA
Venus Williams
 BEL
Justine Henin
6–1, 3–6, 6–0

2002
 USA
Serena Williams
 USA
Venus Williams
7–6(7–4), 6–3

2003
 USA
Serena Williams
 USA
Venus Williams
4–6, 6–4, 6–2

2004
 RUS
Maria Sharapova
 USA
Serena Williams
6–1, 6–4

2005
 USA
Venus Williams
 USA
Lindsay Davenport
4–6, 7–6(7–4), 9–7

2006
 FRA
Amélie Mauresmo
 BEL
Justine Henin
2–6, 6–3, 6–4

2007
 USA
Venus Williams
 FRA
Marion Bartoli
6–4, 6–1

2008
 USA
Venus Williams
 USA
Serena Williams
7–5, 6–4

2009
 USA
Serena Williams
 USA
Venus Williams
7–6(7–3), 6–2

2010
 USA
Serena Williams
 RUS
Vera Zvonareva
6–3, 6–2

2011
 CZE
Petra Kvitová
 RUS
Maria Sharapova
6–3, 6–4

2012
 USA
Serena Williams
 POL
Agnieszka Radwańska
6–1, 5–7, 6–2

2013
 FRA
Marion Bartoli
 GER
Sabine Lisicki
6–1, 6–4

2014
 CZE
Petra Kvitová
 CAN
Eugenie Bouchard
6–3, 6–0

2015
 USA
Serena Williams
 ESP
Garbiñe Muguruza
6–4, 6–4

2016
 USA
Serena Williams
 GER
Angelique Kerber
7–5, 6–3

2017
 ESP
Garbiñe Muguruza
 USA
Venus Williams
7–5, 6–0

2018
 GER
Angelique Kerber
 USA
Serena Williams
6–3, 6–3

text: Statistics[edit]

text: Multiple champions[edit]

text: Title defended in the challenge round

text:
Player

Amateur Era

Open Era

All-time

Years

 Martina Navratilova (USA)[i]
0
9
9
1978, 1979, 1982, 1983, 1984, 1985, 1986, 1987, 1990

 Helen Wills Moody (USA)
8
0
8
1927, 1928, 1929, 1930, 1932, 1933, 1935, 1938

 Dorothea Lambert Chambers (UK)
7
0
7
1903, 1904, 1906, 1910, 1911, 1913, 1914

 Steffi Graf (GER)
0
7
7
1988, 1989, 1991, 1992, 1993, 1995, 1996

 Serena Williams (USA)
0
7
7
2002, 2003, 2009, 2010, 2012, 2015, 2016

 Blanche Bingley (UK)
6
0
6
1886, 1889, 1894, 1897, 1899, 1900

 Suzanne Lenglen (FRA)
6
0
6
1919, 1920, 1921, 1922, 1923, 1925

 Billie Jean King (USA)
2
4
6
1966, 1967, 1968, 1972, 1973, 1975

 Charlotte Cooper Sterry (UK)
5
0
5
1895, 1896, 1898, 1901, 1908

 Lottie Dod (UK)
5
0
5
1887, 1888, 1891, 1892, 1893

 Venus Williams (USA)
0
5
5
2000, 2001, 2005, 2007, 2008

 Louise Brough Clapp (USA)
4
0
4
1948, 1949, 1950, 1955

 Maureen Connolly (USA)
3
0
3
1952, 1953, 1954

 Maria Bueno (BRA)
3
0
3
1959, 1960, 1964

 Margaret Court (AUS)
2
1
3
1963, 1965, 1970

 Chris Evert (USA)
0
3
3
1974, 1976, 1981

 Althea Gibson (USA)
2
0
2
1957, 1958

 Dorothy Round (UK)
2
0
2
1934, 1937

 Kitty McKane Godfree (UK)
2
0
2
1924, 1926

 May Sutton Bundy (USA)
2
0
2
1905, 1907

 Maud Watson (UK)
2
0
2
1884, 1885

 Evonne Goolagong Cawley (AUS)
0
2
2
1971, 1980

 Petra Kvitová (CZE)
0
2
2
2011, 2014

text: Championships by country[edit]

text:
Country

Amateur Era

Open Era

All-time

First title

Last title

 United States (USA)
28
29
57
1905
2016

 United Kingdom (UK)
34
2
36
1884
1977

 Germany (GER)[j]
1
8
9
1931
2018

 France (FRA)
6
2
8
1919
2013

 Australia (AUS)
2
3
5
1963
1980

 Brazil (BRA)
3
0
3
1959
1964

 Czech Republic (CZE)
0
3
3
1998
2014

 Spain (ESP)
0
2
2
1994
2017

  Switzerland (SUI)
0
1
1
1997
1997

 Russia (RUS)
0
1
1
2004
2004


document_title: Star (TV series)

question_text: who plays carlottas mom and sister on star

text: Star (TV series)

text: Cast and characters[edit]

text: Main[edit]

text:
Jude Demorest as Star Davis, a tough 18-year-old who spent her childhood in and out of foster homes after the death of her mother Mary. Wanting to pursue a career in music, she forms a girl group, Take 3 (formerly Big Trouble), with her half sister Simone and best friend Alex in Atlanta. Though she has a lot of talent, her egotistical nature tends to bother others.[9]
Brittany O'Grady as Simone Davis, Star’s biracial 16-year-old half sister. She is rescued by Star from the abusive foster home in which she was placed five years before. While supportive of her sister's ambitions, Simone has dreams of her own, and will do whatever it takes to achieve them. In Season 2, she ends up in state custody for abusing marijuana. She is then liberated from juvie by Ayanna. [9]
Ryan Destiny as Alexandra "Alex" Crane, a wealthy 19-year-old who grew up in New York and Star's best friend. She is looking to step out of the shadows of her famous father and make it on her own, and becomes increasingly involved in political advocacy through her boyfriend Derek.[9]
Amiyah Scott as Cotton Brown, Carlotta's transgender daughter. She works at her mother's salon and helps the girls kickstart their career. She also has a troubled relationship with Carlotta, as the latter has not accepted her daughter's transition, and is not understanding or fully supportive of the difficulties she faces as a trans woman, although she slowly comes around. After stealing money from her boyfriend Elliot, Cotton is sent to prison.
Quincy Brown as Derek Jones, Alexandra's boyfriend who lives next door to the girls. He is a civil rights activist affiliated with the Black Lives Matter movement, and is committed to civil disobedience. After a car accident leaves him paralyzed from the waist down, their relationship becomes strained.
Benjamin Bratt as Jahil Rivera (seasons 1–2),[10] a talent manager who believes Take 3 is his ticket back to the top. However, he is hobbled by both a cocaine addiction and money problems.[9] In Season 2, it is revealed that he faked his death with the help of Carlotta to avoid being framed for Hunter's murder. He ends up forming a new duo with his nephew Angel to compete with Take 3. In the mid-season 2 finale, Angel fires him as manager and he goes on a drug-fueled bender before slipping into a coma.[citation needed] He is shot in a drive-by shooting when shielding Andy and dies in season 2.
Queen Latifah as Carlotta Renee Brown, the owner of an Atlanta beauty salon, who worked with Mary Davis in the R&B duo Mixed Harmony back in the 1990s. She becomes a surrogate mother to the three girls, even though she doesn’t approve of their musical dreams. At the end of Season 1, she takes over as manager from Jahil. Her attempts to make Take 3 a success prove largely ineffective as the girls struggle with their own problems, and in the mid-season 2 finale, her salon is burned down.[9]
Miss Lawrence as Miss Bruce (season 2; recurring season 1), a genderfluid hairdresser who works at Carlotta's salon, taking over from her as owner when she commits to managing Take 3.
Luke James as Noah Brooks (season 2), a formerly top-selling R&B artist at Midtown Sound looking to make a much-needed comeback. He is a charming sweet talker with an ambitious streak, and strikes up a relationships with Alex, Star and Gigi, at first for promotion, but it gradually evolves into an affair.
Michael Michele as Ayanna Floyd (season 2), the unsympathetic president and CEO of Midtown Sound, the record label that signed Take 3. She forms a maternal bond with Simone, even becoming her legal guardian, but also enables her to maintain her addiction to prescription drugs. At the mid-season 2 finale, she is disgraced and removed as president of Midtown after being caught trying to buy the label out from under her father.
Stephen Dorff as Brody Dean (season 2), Star’s long lost biological father who re-emerges as the girls get their first taste of fame, but turns out to have an agenda concerning Hunter's death. Upon discovering the abuse Hunter inflicted on Star, however, he leaves town after murdering Hunter's mother, Arlene. He was electrocuted to death by Arlane's sister.

tag: ul

text: Recurring[edit]

text:
Lenny Kravitz as Roland Crane, a legendary rock star and Alexandra's father. (season 1)[1]
Darius McCrary as Otis Leecan, Simone's abusive foster father. He is murdered by his wife when he tries to force Simone to return home. (season 1)[11]
Chad James Buchanan as Hunter Morgan, Star's ex-boyfriend, who was physically abusive towards her. He is Jahil's godson and a young NFL star, but has secretly been using banned substances to prolong his career. He is killed along with Eva, when a hitman mistakes him for Jahil. (season 1)[12]
Nealla Gordon as Arlene Morgan, Hunter's mother. She didn't approve of Hunter's relationship with Star, and blames her for her son's death. After failing to get a police investigation, she starts blackmailing Star's father Brody to spy on his daughter. However, he stabs her to death after learning about Hunter's abuse. (seasons 1–2)
Naomi Campbell as Rose Spencer-Crane, Alexandra's mother, who struggles with alcoholism. (seasons 1-2)[13]
Tyrese Gibson as Pastor Bobby Harris, Carlotta's ex-boyfriend. He does not accept her transgender daughter Cotton as a woman, and Carlotta eventually breaks up with him. (season 1)[14]
Jasmine Burke as Danielle Jackson, a worker in Carlotta's shop and Gladys Knight's niece. She is shot and killed by police during a traffic stop after they assume she has a gun. (season 1)
Sharlene Taulé as Eva, a Dominican girl whom Jahil saves from a trafficking ring. He later discovers that she is an amateur singer, and has plans to take Star's place in his girl group. She and Hunter are killed on the season finale when a hitman mistakes Hunter for Jahil. (season 1)
Joseline Hernandez as Michelle, a stripper at the Magic City strip club and one of Jahil's lovers. She becomes Cotton's roommate halfway through the first season.[15] However, she ends up betraying Cotton by stealing her money and fleeing Atlanta. (season 1)
Caroline Vreeland as Mary Davis, Star and Simone's mother who died of a drug overdose. Mary was a member of the R&B duo Mixed Harmony with Carlotta in the 1990s.[16]
Jack J. Yang as Elliot, Cotton's boyfriend. He abandons her when she refuses to give up prostitution, and she steals money from him for her surgery. After her release from prison, however, he gives her a secretarial job at his construction firm. He dies after being severely beaten by Cotton's former cellmate, Omari. (seasons 1–2)
Paris Jackson as Rachel Wallace, a social media expert hired by Jahil to promote Take 3. In Season 2, she becomes a consultant for Midtown Records.
Elijah Kelley as Andy, a Harvard graduate and aspiring singer who is an assistant to Ayanna Floyd. Jahil taps him to form a duo with his nephew, Angel. (season 2) [17]
Evan Ross as Angel Rivera, Jahil's nephew who helps him record new music. In turn, Jahil gets him to form a singing duo with Andy. After realizing that his uncle is more concerned with his interests than theirs, however, he fires him as their manager. (season 2)
Lance Gross as Maurice Jetter, A&R at Midtown Records. He helps Carlotta navigate the treacherous currents of the company and his boss, Ayanna. (season 2)
Imani Lewis as Karen, a juvie teen and troubled friend of Simone. After her friend commits suicide, the two start a relationship, but Karen is soon transferred to a new facility after breaking curfew. During the mid-season 2 finale, she tracks down Simone, who vows to take care of her and lets her stay in Carlotta's salon. She is killed in the salon fire. (season 2)
Justin Marcel McManus as Omari, Cotton's former cellmate and lover. He protected Cotton from transphobic inmates during her prison sentence. After getting an early release, he tries to force his way back into Cotton's life. When she breaks off their relationship for Elliot, he violently kills him and seemingly drowns Cotton in her bathtub. (season 2)
Patti LaBelle as Christine Brown, Carlotta's tough but loving mother. (season 2)
Brandy Norwood as Cassie Brown, Carlotta's younger sister. (season 2)
Keke Palmer as Gigi Nixon, a famous, but hotheaded singer with a rough attitude who lands at Midtown Sound after befriending Alex and encourages her romance with Noah. (season 2)

text: Guest stars[edit]

text:
Missy Elliott as Pumpkin, a legendary rapper hired by Hunter to help Star with her block party. In episode 10 of the first season, she helps Jahil produce a new song for Take 3.
Mike Epps as Jay Holland, the former label president of Midtown Sound, but was fired and replaced by Ayanna after Star slept with him to help further Take 3's career.
Jussie Smollett as Jamal Lyon, a member of the Lyon Family, from New York who owns an enterprise and powerful record company in the music Industry (Empire Entertainment) to which he also serves as an artist on the label.
Richard Roundtree as Charles Floyd, a legendary music label executive and Ayanna's father. He has a low opinion of his daughter's business acumen, and threatens to sell the label if she is unable to make it profitable. In the mid-season 2 finale, he receives photos from Jahil implying that Ayanna orchestrated Midtown's financial troubles in order to buy it out with one of his business rivals. Enraged by her disloyalty, he fires her as president and disowns her.
Teyana Taylor as Joyce Sheree, a popular singer who happens to be an old friend of Noah's. Star schemes to get Joyce on one of Take 3's songs after meeting her at a party, but Noah ends up snagging her for his song instead, sparking an argument between them. Joyce ends up overdosing on cough syrup while trying to destress, and winds up hospitalized.

text: Additionally, Big Boi, Tiny, Gladys Knight, Porsha Williams, Kelly Price, Monica Brown, and Quavo make appearances as themselves.

text: Episodes[edit]

text:
Season
Episodes
Originally aired

First aired
Last aired

1
12
December 14, 2016 (2016-12-14)
March 15, 2017 (2017-03-15)

2
18
September 27, 2017 (2017-09-27)
May 23, 2018 (2018-05-23)

text: Production[edit]

text: Development and casting[edit]

text: In August 2015, Fox announced it had ordered a pilot for a potential new musical drama series titled Star from Empire-creator Lee Daniels about three girls forming a girl group.[18] In October that same year, casting for the series began.[19] It was revealed that the series would feature a transgender character. On December 7, 2015, it was announced that Queen Latifah had joined the cast as Carlotta, Jude Demorest as Star, Brittany O'Grady as Simone and Ryan Destiny as Alexandra.[20] On December 11, 2015, it was confirmed that Benjamin Bratt has joined the cast as Jahil, a talent manager.[21] On December 14, 2015, Darius McCrary joined the series as the abusive foster father of Simone (O’Grady).[22] Production for the pilot began in December 2015.[19] The series was picked up, with a 12-episode order, on April 27, 2016.[1] On October 9, 2017, FOX ordered an additional five episodes for the second season, bringing the season total to 18 episodes.[23]

text: Filming[edit]

text: On May 4, 2016, it was announced that Charles Murray would serve as showrunner during its first season.[24] On September 13, 2016, it was announced that Charles Pratt Jr. would replace Murray as the series' showrunner, following his decision to depart the series, due to creative differences.[25][26]

text: Following the conclusion of the show's first season, Pratt stepped down as showrunner and was subsequently replaced by Karin Gist.[27]

text: Reception[edit]

text: Seasonal ratings[edit]

text:
Season
Time slot (ET)
Episodes
Season premiere
Season finales
TV season
Rank
Viewers
(in millions)

Date
Viewers
(in millions)
Date
Viewers
(in millions)

1
Wednesday 9:00 pm
12
December 14, 2016
6.71[28]
March 15, 2017
3.95[29]
2016–17
#76
5.73[30]

2
18
September 27, 2017
5.40[31]
May 23, 2018
3.95[32]
2017–18
TBA
TBA


document_title: Noble gas

question_text: the boiling points of the elements helium neon argon krypton

text: Noble gas

text: History[edit]

text: Noble gas is translated from the German noun Edelgas, first used in 1898 by Hugo Erdmann[1] to indicate their extremely low level of reactivity. The name makes an analogy to the term "noble metals", which also have low reactivity. The noble gases have also been referred to as inert gases, but this label is deprecated as many noble gas compounds are now known.[2] Rare gases is another term that was used,[3] but this is also inaccurate because argon forms a fairly considerable part (0.94% by volume, 1.3% by mass) of the Earth's atmosphere due to decay of radioactive potassium-40.[4]

text: Pierre Janssen and Joseph Norman Lockyer discovered a new element on August 18, 1868 while looking at the chromosphere of the Sun, and named it helium after the Greek word for the Sun, ἥλιος (hḗlios).[5] No chemical analysis was possible at the time, but helium was later found to be a noble gas. Before them, in 1784, the English chemist and physicist Henry Cavendish had discovered that air contains a small proportion of a substance less reactive than nitrogen.[6] A century later, in 1895, Lord Rayleigh discovered that samples of nitrogen from the air were of a different density than nitrogen resulting from chemical reactions. Along with Scottish scientist William Ramsay at University College, London, Lord Rayleigh theorized that the nitrogen extracted from air was mixed with another gas, leading to an experiment that successfully isolated a new element, argon, from the Greek word ἀργός (argós, "idle" or "lazy").[6] With this discovery, they realized an entire class of gases was missing from the periodic table. During his search for argon, Ramsay also managed to isolate helium for the first time while heating cleveite, a mineral. In 1902, having accepted the evidence for the elements helium and argon, Dmitri Mendeleev included these noble gases as group 0 in his arrangement of the elements, which would later become the periodic table.[7]

text: Ramsay continued to search for these gases using the method of fractional distillation to separate liquid air into several components. In 1898, he discovered the elements krypton, neon, and xenon, and named them after the Greek words κρυπτός (kryptós, "hidden"), νέος (néos, "new"), and ξένος (ksénos, "stranger"), respectively. Radon was first identified in 1898 by Friedrich Ernst Dorn,[8] and was named radium emanation, but was not considered a noble gas until 1904 when its characteristics were found to be similar to those of other noble gases.[9] Rayleigh and Ramsay received the 1904 Nobel Prizes in Physics and in Chemistry, respectively, for their discovery of the noble gases;[10][11] in the words of J. E. Cederblom, then president of the Royal Swedish Academy of Sciences, "the discovery of an entirely new group of elements, of which no single representative had been known with any certainty, is something utterly unique in the history of chemistry, being intrinsically an advance in science of peculiar significance".[11]

text: The discovery of the noble gases aided in the development of a general understanding of atomic structure. In 1895, French chemist Henri Moissan attempted to form a reaction between fluorine, the most electronegative element, and argon, one of the noble gases, but failed. Scientists were unable to prepare compounds of argon until the end of the 20th century, but these attempts helped to develop new theories of atomic structure. Learning from these experiments, Danish physicist Niels Bohr proposed in 1913 that the electrons in atoms are arranged in shells surrounding the nucleus, and that for all noble gases except helium the outermost shell always contains eight electrons.[9] In 1916, Gilbert N. Lewis formulated the octet rule, which concluded an octet of electrons in the outer shell was the most stable arrangement for any atom; this arrangement caused them to be unreactive with other elements since they did not require any more electrons to complete their outer shell.[12]

text:
In 1962, Neil Bartlett discovered the first chemical compound of a noble gas, xenon hexafluoroplatinate.[13] Compounds of other noble gases were discovered soon after: in 1962 for radon, radon difluoride (RnF
2),[14] which was identified by radiotracer techniques and in 1963 for krypton, krypton difluoride (KrF
2).[15] The first stable compound of argon was reported in 2000 when argon fluorohydride (HArF) was formed at a temperature of 40 K (−233.2 °C; −387.7 °F).[16]

text: In December 1998, scientists at the Joint Institute for Nuclear Research working in Dubna, Russia bombarded plutonium (Pu) with calcium (Ca) to produce a single atom of element 114,[17] flerovium (Fl).[18] Preliminary chemistry experiments have indicated this element may be the first superheavy element to show abnormal noble-gas-like properties, even though it is a member of group 14 on the periodic table.[19] In October 2006, scientists from the Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory successfully created synthetically oganesson (Og), the seventh element in group 18,[20] by bombarding californium (Cf) with calcium (Ca).[21]

text: Physical and atomic properties[edit]

text:
Property[9][22]
Helium
Neon
Argon
Krypton
Xenon
Radon

Density (g/dm3)
0.1786
0.9002
1.7818
3.708
5.851
9.97

Boiling point (K)
4.4
27.3
87.4
121.5
166.6
211.5

Melting point (K)
0.95
(at 25 bar)
24.7
83.6
115.8
161.7
202.2

Enthalpy of vaporization (kJ/mol)
0.08
1.74
6.52
9.05
12.65
18.1

Solubility in water at 20 °C (cm3/kg)
8.61
10.5
33.6
59.4
108.1
230

Atomic number
2
10
18
36
54
86

Atomic radius (calculated) (pm)
31
38
71
88
108
120

Ionization energy (kJ/mol)
2372
2080
1520
1351
1170
1037

Allen electronegativity[23]
4.16
4.79
3.24
2.97
2.58
2.60

text: The noble gases have weak interatomic force, and consequently have very low melting and boiling points. They are all monatomic gases under standard conditions, including the elements with larger atomic masses than many normally solid elements.[9] Helium has several unique qualities when compared with other elements: its boiling and melting points are lower than those of any other known substance; it is the only element known to exhibit superfluidity; it is the only element that cannot be solidified by cooling under standard conditions—a pressure of 25 standard atmospheres (2,500 kPa; 370 psi) must be applied at a temperature of 0.95 K (−272.200 °C; −457.960 °F) to convert it to a solid.[24] The noble gases up to xenon have multiple stable isotopes. Radon has no stable isotopes; its longest-lived isotope, 222Rn, has a half-life of 3.8 days and decays to form helium and polonium, which ultimately decays to lead.[9] Melting and boiling points generally increase going down the group.

text: The noble gas atoms, like atoms in most groups, increase steadily in atomic radius from one period to the next due to the increasing number of electrons. The size of the atom is related to several properties. For example, the ionization potential decreases with an increasing radius because the valence electrons in the larger noble gases are farther away from the nucleus and are therefore not held as tightly together by the atom. Noble gases have the largest ionization potential among the elements of each period, which reflects the stability of their electron configuration and is related to their relative lack of chemical reactivity.[22] Some of the heavier noble gases, however, have ionization potentials small enough to be comparable to those of other elements and molecules. It was the insight that xenon has an ionization potential similar to that of the oxygen molecule that led Bartlett to attempt oxidizing xenon using platinum hexafluoride, an oxidizing agent known to be strong enough to react with oxygen.[13] Noble gases cannot accept an electron to form stable anions; that is, they have a negative electron affinity.[25]

text: The macroscopic physical properties of the noble gases are dominated by the weak van der Waals forces between the atoms. The attractive force increases with the size of the atom as a result of the increase in polarizability and the decrease in ionization potential. This results in systematic group trends: as one goes down group 18, the atomic radius, and with it the interatomic forces, increases, resulting in an increasing melting point, boiling point, enthalpy of vaporization, and solubility. The increase in density is due to the increase in atomic mass.[22]

text: The noble gases are nearly ideal gases under standard conditions, but their deviations from the ideal gas law provided important clues for the study of intermolecular interactions. The Lennard-Jones potential, often used to model intermolecular interactions, was deduced in 1924 by John Lennard-Jones from experimental data on argon before the development of quantum mechanics provided the tools for understanding intermolecular forces from first principles.[26] The theoretical analysis of these interactions became tractable because the noble gases are monatomic and the atoms spherical, which means that the interaction between the atoms is independent of direction, or isotropic.

text: Chemical properties[edit]

text: The noble gases are colorless, odorless, tasteless, and nonflammable under standard conditions. They were once labeled group 0 in the periodic table because it was believed they had a valence of zero, meaning their atoms cannot combine with those of other elements to form compounds. However, it was later discovered some do indeed form compounds, causing this label to fall into disuse.[9]

text: Configuration[edit]

text: Like other groups, the members of this family show patterns in its electron configuration, especially the outermost shells resulting in trends in chemical behavior:

text:
Z
Element
No. of electrons/shell

2
helium
2

10
neon
2, 8

18
argon
2, 8, 8

36
krypton
2, 8, 18, 8

54
xenon
2, 8, 18, 18, 8

86
radon
2, 8, 18, 32, 18, 8

text: The noble gases have full valence electron shells. Valence electrons are the outermost electrons of an atom and are normally the only electrons that participate in chemical bonding. Atoms with full valence electron shells are extremely stable and therefore do not tend to form chemical bonds and have little tendency to gain or lose electrons.[27] However, heavier noble gases such as radon are held less firmly together by electromagnetic force than lighter noble gases such as helium, making it easier to remove outer electrons from heavy noble gases.

text: As a result of a full shell, the noble gases can be used in conjunction with the electron configuration notation to form the noble gas notation. To do this, the nearest noble gas that precedes the element in question is written first, and then the electron configuration is continued from that point forward. For example, the electron notation of phosphorus is 1s2 2s2 2p6 3s2 3p3, while the noble gas notation is [Ne] 3s2 3p3. This more compact notation makes it easier to identify elements, and is shorter than writing out the full notation of atomic orbitals.[28]

text: Compounds[edit]

text: The noble gases show extremely low chemical reactivity; consequently, only a few hundred noble gas compounds have been formed. Neutral compounds in which helium and neon are involved in chemical bonds have not been formed (although there is some theoretical evidence for a few helium compounds), while xenon, krypton, and argon have shown only minor reactivity.[29] The reactivity follows the order Ne < He < Ar < Kr < Xe < Rn.

text:
In 1933, Linus Pauling predicted that the heavier noble gases could form compounds with fluorine and oxygen. He predicted the existence of krypton hexafluoride (KrF
6) and xenon hexafluoride (XeF
6), speculated that XeF
8 might exist as an unstable compound, and suggested that xenic acid could form perxenate salts.[30][31] These predictions were shown to be generally accurate, except that XeF
8 is now thought to be both thermodynamically and kinetically unstable.[32]

text:
Xenon compounds are the most numerous of the noble gas compounds that have been formed.[33] Most of them have the xenon atom in the oxidation state of +2, +4, +6, or +8 bonded to highly electronegative atoms such as fluorine or oxygen, as in xenon difluoride (XeF
2), xenon tetrafluoride (XeF
4), xenon hexafluoride (XeF
6), xenon tetroxide (XeO
4), and sodium perxenate (Na
4XeO
6). Xenon reacts with fluorine to form numerous xenon fluorides according to the following equations:

text:
Some of these compounds have found use in chemical synthesis as oxidizing agents; XeF
2, in particular, is commercially available and can be used as a fluorinating agent.[34] As of 2007, about five hundred compounds of xenon bonded to other elements have been identified, including organoxenon compounds (containing xenon bonded to carbon), and xenon bonded to nitrogen, chlorine, gold, mercury, and xenon itself.[29][35] Compounds of xenon bound to boron, hydrogen, bromine, iodine, beryllium, sulphur, titanium, copper, and silver have also been observed but only at low temperatures in noble gas matrices, or in supersonic noble gas jets.[29]

text: In theory, radon is more reactive than xenon, and therefore should form chemical bonds more easily than xenon does. However, due to the high radioactivity and short half-life of radon isotopes, only a few fluorides and oxides of radon have been formed in practice.[36]

text: Krypton is less reactive than xenon, but several compounds have been reported with krypton in the oxidation state of +2.[29] Krypton difluoride is the most notable and easily characterized. Under extreme conditions, krypton reacts with fluorine to form KrF2 according to the following equation:

text: Compounds in which krypton forms a single bond to nitrogen and oxygen have also been characterized,[37] but are only stable below −60 °C (−76 °F) and −90 °C (−130 °F) respectively.[29]

text: Krypton atoms chemically bound to other nonmetals (hydrogen, chlorine, carbon) as well as some late transition metals (copper, silver, gold) have also been observed, but only either at low temperatures in noble gas matrices, or in supersonic noble gas jets.[29] Similar conditions were used to obtain the first few compounds of argon in 2000, such as argon fluorohydride (HArF), and some bound to the late transition metals copper, silver, and gold.[29] As of 2007, no stable neutral molecules involving covalently bound helium or neon are known.[29]

text: The noble gases—including helium—can form stable molecular ions in the gas phase. The simplest is the helium hydride molecular ion, HeH+, discovered in 1925.[38] Because it is composed of the two most abundant elements in the universe, hydrogen and helium, it is believed to occur naturally in the interstellar medium, although it has not been detected yet.[39] In addition to these ions, there are many known neutral excimers of the noble gases. These are compounds such as ArF and KrF that are stable only when in an excited electronic state; some of them find application in excimer lasers.

text: In addition to the compounds where a noble gas atom is involved in a covalent bond, noble gases also form non-covalent compounds. The clathrates, first described in 1949,[40] consist of a noble gas atom trapped within cavities of crystal lattices of certain organic and inorganic substances. The essential condition for their formation is that the guest (noble gas) atoms must be of appropriate size to fit in the cavities of the host crystal lattice. For instance, argon, krypton, and xenon form clathrates with hydroquinone, but helium and neon do not because they are too small or insufficiently polarizable to be retained.[41] Neon, argon, krypton, and xenon also form clathrate hydrates, where the noble gas is trapped in ice.[42]

text:
Noble gases can form endohedral fullerene compounds, in which the noble gas atom is trapped inside a fullerene molecule. In 1993, it was discovered that when C
60, a spherical molecule consisting of 60 carbon atoms, is exposed to noble gases at high pressure, complexes such as He@C
60 can be formed (the @ notation indicates He is contained inside C
60 but not covalently bound to it).[43] As of 2008, endohedral complexes with helium, neon, argon, krypton, and xenon have been obtained.[44] These compounds have found use in the study of the structure and reactivity of fullerenes by means of the nuclear magnetic resonance of the noble gas atom.[45]

text:
Noble gas compounds such as xenon difluoride (XeF
2) are considered to be hypervalent because they violate the octet rule. Bonding in such compounds can be explained using a three-center four-electron bond model.[46][47] This model, first proposed in 1951, considers bonding of three collinear atoms. For example, bonding in XeF
2 is described by a set of three molecular orbitals (MOs) derived from p-orbitals on each atom. Bonding results from the combination of a filled p-orbital from Xe with one half-filled p-orbital from each F atom, resulting in a filled bonding orbital, a filled non-bonding orbital, and an empty antibonding orbital. The highest occupied molecular orbital is localized on the two terminal atoms. This represents a localization of charge which is facilitated by the high electronegativity of fluorine.[48]

text: The chemistries of the heavier noble gases, krypton and xenon, are well established. The chemistry of the lighter ones, argon and helium, is still at an early stage, while a neon compound is yet to be identified.

text: Occurrence and production[edit]

text: The abundances of the noble gases in the universe decrease as their atomic numbers increase. Helium is the most common element in the universe after hydrogen, with a mass fraction of about 24%. Most of the helium in the universe was formed during Big Bang nucleosynthesis, but the amount of helium is steadily increasing due to the fusion of hydrogen in stellar nucleosynthesis (and, to a very slight degree, the alpha decay of heavy elements).[49][50] Abundances on Earth follow different trends; for example, helium is only the third most abundant noble gas in the atmosphere. The reason is that there is no primordial helium in the atmosphere; due to the small mass of the atom, helium cannot be retained by the Earth's gravitational field.[51] Helium on Earth comes from the alpha decay of heavy elements such as uranium and thorium found in the Earth's crust, and tends to accumulate in natural gas deposits.[51] The abundance of argon, on the other hand, is increased as a result of the beta decay of potassium-40, also found in the Earth's crust, to form argon-40, which is the most abundant isotope of argon on Earth despite being relatively rare in the Solar System. This process is the basis for the potassium-argon dating method.[52] Xenon has an unexpectedly low abundance in the atmosphere, in what has been called the missing xenon problem; one theory is that the missing xenon may be trapped in minerals inside the Earth's crust.[53] After the discovery of xenon dioxide, research showed that Xe can substitute for Si in quartz.[54] Radon is formed in the lithosphere by the alpha decay of radium. It can seep into buildings through cracks in their foundation and accumulate in areas that are not well ventilated. Due to its high radioactivity, radon presents a significant health hazard; it is implicated in an estimated 21,000 lung cancer deaths per year in the United States alone.[55]

text:
Abundance
Helium
Neon
Argon
Krypton
Xenon
Radon

Solar System (for each atom of silicon)[56]
2343
2.148
0.1025
5.515 × 10−5
5.391 × 10−6
–

Earth's atmosphere (volume fraction in ppm)[57]
5.20
18.20
9340.00
1.10
0.09
(0.06–18) × 10−19[58]

Igneous rock (mass fraction in ppm)[22]
3 × 10−3
7 × 10−5
4 × 10−2
–
–
1.7 × 10−10

text:
Gas
2004 price (USD/m3)[59]

Helium (industrial grade)
4.20–4.90

Helium (laboratory grade)
22.30–44.90

Argon
2.70–8.50

Neon
60–120

Krypton
400–500

Xenon
4000–5000

text: For large-scale use, helium is extracted by fractional distillation from natural gas, which can contain up to 7% helium.[60]

text: Neon, argon, krypton, and xenon are obtained from air using the methods of liquefaction of gases, to convert elements to a liquid state, and fractional distillation, to separate mixtures into component parts. Helium is typically produced by separating it from natural gas, and radon is isolated from the radioactive decay of radium compounds.[9] The prices of the noble gases are influenced by their natural abundance, with argon being the cheapest and xenon the most expensive. As an example, the adjacent table lists the 2004 prices in the United States for laboratory quantities of each gas.

text: Applications[edit]

text: Noble gases have very low boiling and melting points, which makes them useful as cryogenic refrigerants.[61] In particular, liquid helium, which boils at 4.2 K (−268.95 °C; −452.11 °F), is used for superconducting magnets, such as those needed in nuclear magnetic resonance imaging and nuclear magnetic resonance.[62] Liquid neon, although it does not reach temperatures as low as liquid helium, also finds use in cryogenics because it has over 40 times more refrigerating capacity than liquid helium and over three times more than liquid hydrogen.[58]

text: Helium is used as a component of breathing gases to replace nitrogen, due its low solubility in fluids, especially in lipids. Gases are absorbed by the blood and body tissues when under pressure like in scuba diving, which causes an anesthetic effect known as nitrogen narcosis.[63] Due to its reduced solubility, little helium is taken into cell membranes, and when helium is used to replace part of the breathing mixtures, such as in trimix or heliox, a decrease in the narcotic effect of the gas at depth is obtained.[64] Helium's reduced solubility offers further advantages for the condition known as decompression sickness, or the bends.[9][65] The reduced amount of dissolved gas in the body means that fewer gas bubbles form during the decrease in pressure of the ascent. Another noble gas, argon, is considered the best option for use as a drysuit inflation gas for scuba diving.[66] Helium is also used as filling gas in nuclear fuel rods for nuclear reactors.[67]

text: Since the Hindenburg disaster in 1937,[68] helium has replaced hydrogen as a lifting gas in blimps and balloons due to its lightness and incombustibility, despite an 8.6%[69] decrease in buoyancy.[9]

text: In many applications, the noble gases are used to provide an inert atmosphere. Argon is used in the synthesis of air-sensitive compounds that are sensitive to nitrogen. Solid argon is also used for the study of very unstable compounds, such as reactive intermediates, by trapping them in an inert matrix at very low temperatures.[70] Helium is used as the carrier medium in gas chromatography, as a filler gas for thermometers, and in devices for measuring radiation, such as the Geiger counter and the bubble chamber.[59] Helium and argon are both commonly used to shield welding arcs and the surrounding base metal from the atmosphere during welding and cutting, as well as in other metallurgical processes and in the production of silicon for the semiconductor industry.[58]

text: Noble gases are commonly used in lighting because of their lack of chemical reactivity. Argon, mixed with nitrogen, is used as a filler gas for incandescent light bulbs.[58] Krypton is used in high-performance light bulbs, which have higher color temperatures and greater efficiency, because it reduces the rate of evaporation of the filament more than argon; halogen lamps, in particular, use krypton mixed with small amounts of compounds of iodine or bromine.[58] The noble gases glow in distinctive colors when used inside gas-discharge lamps, such as "neon lights". These lights are called after neon but often contain other gases and phosphors, which add various hues to the orange-red color of neon. Xenon is commonly used in xenon arc lamps which, due to their nearly continuous spectrum that resembles daylight, find application in film projectors and as automobile headlamps.[58]

text: The noble gases are used in excimer lasers, which are based on short-lived electronically excited molecules known as excimers. The excimers used for lasers may be noble gas dimers such as Ar2, Kr2 or Xe2, or more commonly, the noble gas is combined with a halogen in excimers such as ArF, KrF, XeF, or XeCl. These lasers produce ultraviolet light which, due to its short wavelength (193 nm for ArF and 248 nm for KrF), allows for high-precision imaging. Excimer lasers have many industrial, medical, and scientific applications. They are used for microlithography and microfabrication, which are essential for integrated circuit manufacture, and for laser surgery, including laser angioplasty and eye surgery.[71]

text: Some noble gases have direct application in medicine. Helium is sometimes used to improve the ease of breathing of asthma sufferers.[58] Xenon is used as an anesthetic because of its high solubility in lipids, which makes it more potent than the usual nitrous oxide, and because it is readily eliminated from the body, resulting in faster recovery.[72] Xenon finds application in medical imaging of the lungs through hyperpolarized MRI.[73] Radon, which is highly radioactive and is only available in minute amounts, is used in radiotherapy.[9]

text: Discharge color[edit]

text:
Colors and spectra (bottom row) of electric discharge in noble gases; only the second row represents pure gases.

Helium
Neon
Argon
Krypton
Xenon

text: The color of gas discharge emission depends on several factors, including the following:[74]

text:
discharge parameters (local value of current density and electric field, temperature, etc. – note the color variation along the discharge in the top row);
gas purity (even small fraction of certain gases can affect color);
material of the discharge tube envelope – note suppression of the UV and blue components in the bottom-row tubes made of thick household glass.