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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/cm
3
)
Reactions:
[
Ref.1
]
2B + 3F
2
→ 2BF
3
Half-life:
10
5
B = stable (mass excess 12050,7 keV (isotopic abundance 19,9%))
11
5
B = stable (mass excess 8667,9 keV (isotopic abundance 80,1%))
12
5
B = 0.0202 s (β
-
(100%), β
-
α (1.6%))
13
5
B = 0.0174 s (β
-
)
14
5
B = 14 ms (β
-
)
15
5
B = 10.4 ms (β
-
)
16
5
B = < 0.19 ns ()
17
5
B = 5.1 ms (β
-
)
18
5
B = < 26 ns ()
19
5
B = 3.3 ms (β
-
)
7
5
B = 0.0004 as (p)
8
5
B = 0.770 s (β
+
α)
9
5
B = 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 Δ
f
H
0
(298.15 K, kJ/mol):
0 (s)
Standard molar Gibbs energy of formation Δ
f
G
0
(298.15 K, kJ/mol):
0 (s)
Standard molar entropy S
0
(298.15 K, J/(mol·K)):
5.86 (s)
Molar heat capacity at constant pressure C
p
(298.15 K, J/(mol·K)):
11.1 (s)
Molar enthalpy (heat) of fusion Δ
fus
H (kJ/mol):
23
Enthalpy (heat) of vaporization Δ
vap
H (kJ/mol):
530
References:
Bretherick's Handbook of Reactive Chemical Hazards. - 6 ed., Vol. 1. - Butterworth-Heinemann, 1999. - pp. 58-59
Handbook of Chemistry and Physics. - CRC Press, Inc., 2002. - pp. 11-51 - 11-52
Гринвуд Н., Эрншо А. Химия элементов. - Т.1. - М.: БИНОМ. Лаборатория знаний, 2008. - pp. 139-144 [Russian]
Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 50 [Russian]
Некрасов Б.В. Основы общей химии. - Т.2. - М.: Химия, 1973. - pp. 5-6, 8-9 [Russian]
Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 56 [Russian]
Химическая энциклопедия. - Т. 1. - М.: Советская энциклопедия, 1988. - pp. 299-300 [Russian]
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© Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru