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Properties of substance:

selenic acid

Group of substances:

inorganic

Physical appearance:

colorless hexagonal crystals

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

H2O4Se

Structural formula as text:

H2SeO4

Molar/atomic mass: 144.97

Melting point (°C):

62

Decomposition temperature (°C):

260

CAS №: 7783-08-6

Solubility (g/100 g of solvent):

ammonia liquid : insoluble [Ref.]
sulfuric acid: soluble [Ref.]
water: 566 (20°C) [Ref.]
water: 1720 (40°C) [Ref.]
water: miscible (60°C) [Ref.]

Properties of solutions:

49,4% (wt.), solvent - water
  Freezing point (°C) = -83.4
80% (wt.), solvent - water
  Density (g/cm3) = 2.122 (20°)
85% (wt.), solvent - water

Hygroscopic:

yes

Interatomic distances and bond angles:

Interatomic distances (in pm): 161 (Se-O) [crystals]

Density:

2.95 (15°C, g/cm3)

Reactions of synthesis:

  1. [Ref.1aster, Ref.2aster, Ref.3aster, Ref.4aster, Ref.5aster]
    SeO2 + H2O2 → H2SeO4

Reactions:

  1. [Ref.1]
    2Au + 3H2SeO4 → Au2O(SeO3)2 + H2SeO3 + 2H2O

Electrode potential:

SeO42- + 4H+ + 2e- → H2SeO3 + H2O, E = 1.15 V (water, °C)

Dissociation:

pKa (1) = -3 (25°C, water)
pKa (2) = 1.9 (25°C, water)

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

-532.6 (s)

References:

  1. CRC Handbook of Chemistry and Physics. - 95ed. - CRC Press, 2014. - pp. 4-86
  2. Journal of Physical Chemistry. - 1909. - Vol. 13, No. 7. - pp. 505-511 [DOI: 10.1021/j150106a001]
  3. Seidell A. Solubilities of inorganic and metal organic compounds. - 3ed., vol.1. - New York: D. Van Nostrand Company, 1940. - pp. 601
  4. The Merck Index 11th ed., Merck & Company, 1989. - pp. 1336
  5. Гринвуд Н., Эрншо А. Химия элементов. - Т.2. - М.: БИНОМ. Лаборатория знаний, 2008. - pp. 130 [Russian]
  6. Ефимов А.И. и др. Свойства неорганических соединений. Справочник. - Л.: Химия, 1983. - pp. 190-191 [Russian]
  7. Некрасов Б.В. Основы общей химии. - Т.1. - М.: Химия, 1973. - pp. 362 [Russian]
  8. Редкие и рассеянные элементы. Химия и технология. - Кн. 3. - М.: Мисис, 2003. - pp. 244-246 [Russian]
  9. Справочник по растворимости. - Т.1, Кн.1. - М.-Л.: ИАН СССР, 1961. - pp. 342 [Russian]
  10. Справочник химика. - Т. 2. - Л.-М.: Химия, 1964. - pp. 200-201 [Russian]
  11. Справочник химика. - Т. 3. - М.-Л.: Химия, 1965. - pp. 79 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru