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Properties of substance:
diphosphoric acid
Group of substances:
inorganic
Physical appearance:
colorless crystals
Empirical formula (Hill's system for organic substances):
H
4
O
7
P
2
Structural formula as text:
H4P2O7
Molar/atomic mass: 177.97
Melting point (°C):
61
Decomposition temperature (°C):
300
Solubility (g/100 g of solvent):
diethyl ether
: very soluble [
Ref.
]
ethanol
: very soluble [
Ref.
]
water
: 709 (23°C) [
Ref.
]
water
: reaction (100°C) [
Ref.
]
Dissociation:
pK
a
(1) = 0.85 (18°C, water)
pK
a
(2) = 1.95 (25°C, water)
pK
a
(3) = 6.68 (25°C, water)
pK
a
(4) = 9.39 (25°C, water)
Standard molar enthalpy (heat) of formation Δ
f
H
0
(298.15 K, kJ/mol):
-2242 (s)
Molar enthalpy (heat) of fusion Δ
fus
H (kJ/mol):
9.2
Standard molar enthalpy (heat) of formation Δ
f
H
0
(298.15 K, kJ/mol):
-2231.7 (l)
LD
50
(mg/kg):
1170 (mice, )
References:
CRC Handbook of Chemistry and Physics. - 90ed. - CRC Press, 2010. - pp. 5-14
Некрасов Б.В. Основы общей химии. - Т.1. - М.: Химия, 1973. - pp. 450 [Russian]
Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 109 [Russian]
Справочник по растворимости. - Т.1, Кн.1. - М.-Л.: ИАН СССР, 1961. - pp. 333 [Russian]
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© Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru