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Properties of substance:

caesium

Synonyms:

cesium

Group of substances:

inorganic

Physical appearance:

yellowish cubic metal

Empirical formula (Hill's system for organic substances):

Cs

Structural formula as text:

Cs

Molar/atomic mass: 132.91

Melting point (°C):

28.5

Boiling point (°C):

672

Solubility (g/100 g of solvent):

ammonia liquid : 333.5 (-50°C) [Ref.]
cesium chloride fused: 7.8 (646°C) [Ref.]
ethanol: reaction [Ref.]
ethylenediamine: 0.797 (20°C) [Ref.]
hexamethylphosphoric triamide: very soluble [Ref.]
lithium molten: soluble [Ref.]
mercury: 4.54 (18°C) [Ref.]
methylamine: soluble [Ref.]
water: reaction [Ref.]

Numerical data:

Year of discovery: 1860
Ionization Potentials (Electronvolts): 3.89397
Ionization Potentials (Electronvolts): 25.1
Hardness on the Mohs’ scale: 0.2

Density:

1.9039 (20°C, g/cm3)
1.836 (28.5°C, g/cm3)
1.887 (28.5°C, g/cm3)
1.78 (127°C, g/cm3)
1.552 (527°C, g/cm3)

Reactions:

  1. [Ref.1]
    2Cs/Hg + 2H2O → 2CsOH + H2 + 2Hg
  2. [Ref.1aster]
    4Cs + O2 → 2Cs2O

Half-life:

11255Cs = 490 μs (p (about 100%))
11355Cs = 17.7 μs (p (100%))
11455Cs = 570 ms (β+ (about 100%), β+p (8.7%), α (0.018%), β+α (0.19%))
11555Cs = 1.4 s (β+ (100%), β+p (0.07%))
11655Cs = 700 ms (β+ (100%), β+p (0.28%), β+α (0.049%))
11755Cs = 8.4 s (β+ (100%))
117m55Cs = 6.5 s (β+ (100%))
11855Cs = 14 s (β+ (100%), β+p (0.021%), β+α (0.0012%))
11955Cs = 43.0 s (β+ (100%))
119m55Cs = 30.4 s (β+ (100%))
12055Cs = 60.4 s (β+ (100%))
12155Cs = 155 s (β+ (100%))
121m55Cs = 122 s (β+ (83%), internal transition (17%))
12255Cs = 21.18 s (β+ (100%))
122n55Cs = 3.70 min (β+ (100%))
12355Cs = 5.88 min (β+ (100%))
123m55Cs = 1.64 s (internal transition (100%))
123n55Cs = 114 ns (internal transition (100%))
12455Cs = 30.9 s (β+ (100%))
124m55Cs = 6.3 s (internal transition (100%))
12555Cs = 46.7 min (β+ (100%))
125m55Cs = 900 μs (internal transition (100%))
12655Cs = 1.64 min (β+ (100%))
126n55Cs = 171 μs (internal transition (100%))
12755Cs = 6.25 h (β+ (100%))
127m55Cs = 55 μs (internal transition (100%))
12855Cs = 3.640 min (β+ (100%))
12955Cs = 32.06 h (β+ (100%))
129m55Cs = 718 ns (internal transition (100%))
13055Cs = 29.21 min (β+ (98.4%), β- (1.6%))
13155Cs = 9.689 d (electron capture (100%))
13255Cs = 6.480 d (β+ (98.13%), β- (1.87%))
13355Cs = stable ( (isotopic abundance 100%))
13455Cs = 2.0648 y (β- (100%))
134m55Cs = 2.903 h (internal transition (100%))
13555Cs = 2 300 000 y (β- (100%))
135m55Cs = 53 min (internal transition (100%))
13655Cs = 13.16 d (β- (100%))
136m55Cs = 17.5 s (internal transition (?))
13755Cs = 30.1671 y (β- (100%))
13855Cs = 33.41 min (β- (100%))
13955Cs = 9.27 min (β- (100%))
14055Cs = 63.7 s (β- (100%))
14155Cs = 24.84 s (β- (100%), β-n (0.035%))
14255Cs = 1.684 s (β- (100%), β-n (0.090%))
14355Cs = 1.791 s (β- (100%), β-n (1.64%))
14455Cs = 994 ms (β- (100%), β-n (3.03%))
14555Cs = 582 ms (β- (100%), β-n (14.7%))
14655Cs = 323 ms (β- (100%), β-n (14.2%))
14755Cs = 230 ms (β- (100%), β-n (28.5%))

Vapour pressure (Torr):

1 (278°C)
10 (387°C)
100 (515°C)
200 (570°C)
400 (635°C)

Electrode potential:

Cs+ + e- → Cs, E = -2.923 V (water, 25°C)

Viscosity (mPa·s):

0.63 (43.4°C)
0.475 (99.6°C)
0.375 (168°C)

Standard molar enthalpy (heat) of formation ΔfH0 (298.15 K, kJ/mol):

0 (s)

Standard molar Gibbs energy of formation ΔfG0 (298.15 K, kJ/mol):

0 (s)

Standard molar entropy S0 (298.15 K, J/(mol·K)):

84.35 (s)

Molar heat capacity at constant pressure Cp (298.15 K, J/(mol·K)):

32 (s)

Molar enthalpy (heat) of fusion ΔfusH (kJ/mol):

2.09

Enthalpy (heat) of vaporization ΔvapH (kJ/mol):

68.28

Critical temperature (°C):

1427

References:

  1. Journal of the American Chemical Society. - 1939. - Vol. 61, No. 3. - pp. 709-715 [DOI: 10.1021/ja01872a049]
  2. Гринвуд Н., Эрншо А. Химия элементов. - Т.1. - М.: БИНОМ. Лаборатория знаний, 2008. - pp. 83 [Russian]
  3. Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 52 [Russian]
  4. Локшин Э.П., Воскобойников Н.Б. Рубидий и цезий. - Апатиты, 1996 [Russian]
  5. Методы элементоорганической химии: Литий, натрий, калий, рубидий, цезий. - Кн.2. - М.: Наука, 1971. - pp. 1141-1143 [Russian]
  6. Некрасов Б.В. Основы общей химии. - Т.2. - М.: Химия, 1973. - pp. 220-226 [Russian]
  7. Неорганические синтезы. - Сб. 1. - М.: ИИЛ, 1951. - pp. 10 [Russian]
  8. Плющев В.Е., Степин Б.Д. Аналитическая химия рубидия и цезия. - М.: Наука, 1975. - pp. 12-13 [Russian]
  9. Плющев В.Е., Степин Б.Д. Химия и технология соединений лития, рубидия и цезия. - М.: Химия, 1970. - pp. 72-80 [Russian]
  10. Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 111 [Russian]
  11. Редкие и рассеянные элементы. Химия и технология. - Кн. 1. - М.: Мисис, 1996. - pp. 68-70 [Russian]
  12. Свойства элементов. - под общей редакцией Дрица М.Е. - М.: Металлургия, 1985. - pp. 54-60 [Russian]
  13. Филянд М.А., Семенова Е.И. Свойства редких элементов. - 2-е изд. - М.: Металлургия, 1964. - pp. 232-240 [Russian]
  14. Химическая энциклопедия. - Т. 5. - М.: Советская энциклопедия, 1999. - pp. 331-333 [Russian]
  15. Энциклопедия для детей. - Т.17: Химия. - М.: Аванта+, 2004. - pp. 184 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru