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Properties of substance:

niobium(V) oxide

Group of substances:

inorganic

Physical appearance:

white monoclinic crystals

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

Nb2O5

Structural formula as text:

Nb2O5

Molar/atomic mass: 265.81

Melting point (°C):

1490

Boiling point (°C):

2927

Solubility (g/100 g of solvent):

hydrogen fluoride : reaction [Ref.]
water: insoluble [Ref.]

Density:

4.95 (20°C, g/cm3)

Permittivity (dielectric constant):

50 (20°C)

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

-1898 (s)

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

-1764.1 (s)

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

137.2 (s)

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

132.09 (s)

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

102.9

Enthalpy (heat) of vaporization at boiling point ΔvapH (kJ/mol)

334.94 (l) [Ref.]

LD50 (mg/kg):

4000 (mice, oral)

References:

  1. Гибало И.М. Аналитическая химия ниобия и тантала. - М.: Наука, 1967. - pp. 33-35 [Russian]
  2. Некрасов Б.В. Основы общей химии. - Т.1. - М.: Химия, 1973. - pp. 484 [Russian]
  3. Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 88 [Russian]
  4. Физико-химические свойства окислов. Справочник. - 2 изд. - М.: Металлургия, 1978. - pp. 468 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru