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Properties of substance:

boron

Group of substances:

inorganic

Physical appearance:

crystals

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

B

Structural formula as text:

B

Molar/atomic mass: 10.811

Melting point (°C):

2075

Boiling point (°C):

3700

CAS №: 7440-42-8

Solubility (g/100 g of solvent):

diethyl ether: insoluble [Ref.]
ethanol: insoluble [Ref.]
water: insoluble [Ref.]

Numerical data:

Year of discovery: 1808
Vickers hardness (GPa): 45

Density:

2.34 (20°C, g/cm3)

Reactions:

  1. [Ref.1]
    2B + 3F2 → 2BF3

Half-life:

105B = stable (mass excess 12050,7 keV (isotopic abundance 19,9%))
115B = stable (mass excess 8667,9 keV (isotopic abundance 80,1%))
125B = 0.0202 s (β- (100%), β-α (1.6%))
135B = 0.0174 s (β-)
145B = 14 ms (β-)
155B = 10.4 ms (β-)
165B = < 0.19 ns ()
175B = 5.1 ms (β-)
185B = < 26 ns ()
195B = 3.3 ms (β-)
75B = 0.0004 as (p)
85B = 0.770 s (β+α)
95B = 0.8 as (p2α)

Vapour pressure (Torr):

0.01 (2136°C)
0.1 (2358°C)
1 (2625°C)
10 (2957°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)):

5.86 (s)

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

11.1 (s)

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

23

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

530

References:

  1. Bretherick's Handbook of Reactive Chemical Hazards. - 6 ed., Vol. 1. - Butterworth-Heinemann, 1999. - pp. 58-59
  2. Handbook of Chemistry and Physics. - CRC Press, Inc., 2002. - pp. 11-51 - 11-52
  3. Гринвуд Н., Эрншо А. Химия элементов. - Т.1. - М.: БИНОМ. Лаборатория знаний, 2008. - pp. 139-144 [Russian]
  4. Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 50 [Russian]
  5. Некрасов Б.В. Основы общей химии. - Т.2. - М.: Химия, 1973. - pp. 5-6, 8-9 [Russian]
  6. Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 56 [Russian]
  7. Химическая энциклопедия. - Т. 1. - М.: Советская энциклопедия, 1988. - pp. 299-300 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru