Westerveldite

Formula : FeAs

Family: 
Arsenide
Space group: 
Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pnam

Dernière mise à jour le 25.01.2021

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
 V°
cm3·mol-1
 ΔGºf
J·mol-1
 ΔHºf
J·mol-1
 Sº
J·mol-1·k-1
 CP
J·mol-1·K-1
130.769 16.640 (Ref.: 08per/pok) Perfetti E., Pokrovski G., Ballerat-Busserolles K., Majer V., Gibert F. (2008) Densities and heat capacities of aqueous arsenious and arsenic acid solutions to 350 C and 300 bar, and revised thermodynamic properties of As(OH)3(aq), AsO(OH)3(aq) and iron sulfarsenide minerals. Geochimica et Cosmochimica Acta 72, 713-731 -43360 (Ref.: 08per/pok) Perfetti E., Pokrovski G., Ballerat-Busserolles K., Majer V., Gibert F. (2008) Densities and heat capacities of aqueous arsenious and arsenic acid solutions to 350 C and 300 bar, and revised thermodynamic properties of As(OH)3(aq), AsO(OH)3(aq) and iron sulfarsenide minerals. Geochimica et Cosmochimica Acta 72, 713-731 -43512 (Ref.: Internal calculation) 62.500 (Ref.: 08per/pok) Perfetti E., Pokrovski G., Ballerat-Busserolles K., Majer V., Gibert F. (2008) Densities and heat capacities of aqueous arsenious and arsenic acid solutions to 350 C and 300 bar, and revised thermodynamic properties of As(OH)3(aq), AsO(OH)3(aq) and iron sulfarsenide minerals. Geochimica et Cosmochimica Acta 72, 713-731 50.36 (Ref.: 08per/pok) Perfetti E., Pokrovski G., Ballerat-Busserolles K., Majer V., Gibert F. (2008) Densities and heat capacities of aqueous arsenious and arsenic acid solutions to 350 C and 300 bar, and revised thermodynamic properties of As(OH)3(aq), AsO(OH)3(aq) and iron sulfarsenide minerals. Geochimica et Cosmochimica Acta 72, 713-731
CP(T) = a + b·T + ·c·T-2 (T in Kelvin)
a
J·mol-1·K-1
 b * 103
J·mol-1·K-2
 c * 10-5
J·K·mol-1
 Maier Kelley Ref.
27.95 46.50 7.60 (Ref.: 08per/pok) Perfetti E., Pokrovski G., Ballerat-Busserolles K., Majer V., Gibert F. (2008) Densities and heat capacities of aqueous arsenious and arsenic acid solutions to 350 C and 300 bar, and revised thermodynamic properties of As(OH)3(aq), AsO(OH)3(aq) and iron sulfarsenide minerals. Geochimica et Cosmochimica Acta 72, 713-731
Reaction properties

Westerveldite + 2H+ + 0.5H2O ⇌ AsH3 + Fe+2 + 0.25O2

298.15 K, 1 bar log10K: -30.68 ΔH°r:161563 J·mol-1 (Ref.: Internal calculation)
T(°C) 0 25 60 100 150 200 250 300
log10K -33.24 -30.68 -27.67 -24.85 -22.02 -19.75 -17.90 -16.39
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
-133.322493 -0.020500 -3250.998318 48.822128 -102075.231515