Adamite

Formula : Zn2AsO4(OH)

Family: 
Arsenate
Space group: 
Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) space Group: Pnnm
Dana class: 
41.06.06.03 (41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen ; (41.06)where (A)2 (XO4) Zq ; (41.06.06)Olivenite Group
High temperature: 
Adamite is stable under normal atmospheric conditions
Geological context: 
oxidized zones of Zn and As hydrothermal ore deposits

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
286.707 64.574 (Ref.: 00bla/bid) Bladh K.W., Bideaux R.A., Anthony-Morton E., Nichols B.G. (2000) The Handbook of Mineralogy Volume IV, Mineralogical Society of America. -1252162 (Ref.: 01gas/aza) Gaskova O., Azaroual M., Piantone, P., Lassin A. (2001) - Arsenic behaviour in subsurface hydrogeochemical systems - A critical review of thermodynamic data forarsenic minerals and aqueous species - A compilation of arsenic surface complexation reactions. BRGM Report RP-51356-FR, 78 p.
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.
Reaction properties

Adamite + 3H+ ⇌ H2AsO4- + 2Zn+2 + H2O

298.15 K, 1 bar log10K: 5.71 ΔH°r: J·mol-1 (Ref.: )
T(°C) 0 25 60 100 150 200 250 300
log10K 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71
log10K(T) = A + B·T + C·T-1 + D·log10(T) + E·T−2 (T in Kelvin)
A B C D E
5.711016 0.000000 0.000000 0.000000 0.000000