Brushite

Formula : CaHPO4:2H2O

Space group: 
Monoclinic - Prismatic HM symbol (2/m) Space Group: I2/a
Dana class: 
39.1.1.1VII - 39 Hydrated Acid Phosphates, etc ; 39.1 Hydrated Acid Phosphates, etc A+ [HXO4] . x(H2O) ; 39.1.1
High temperature: 
Sable at room temperature
Geological context: 
Occurs as the most common cave minerals, in guano deposits, and in phosphorites, formed at low pH by reaction of phosphate-rich solutions with calcite and clay.

Dernière mise à jour le 11.06.2018

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
cm3·mol-1
ΔGºf
J·mol-1
ΔHºf
J·mol-1
J·mol-1·k-1
CP
J·mol-1·K-1
172.088 73.920 -2160814 -2409885 189.450 200.45
Reaction properties

Brushite + H+ ⇌ Ca+2 + H2PO4- + 2H2O

298.15 K, 1 bar log10K: 0.60 ΔH°r: -7375 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 0.70 0.60 0.43 0.21 -0.14 -0.59 -1.16 -1.95