Mineral Formula Crystal system Arsenic solubility conditionsa ΔfG ° (kJ∙mol-1)
Arsenolite As2O3 Cubic 11.1 g/L; 22°C –576.34
Claudetite As2O3 Monoclinic 10.1 g/L; 22°C –576.53
AFA/pitticite Fex(AsO4)y(SO4)z•nH2O Amorphous 75-15370 mg/L at pH   0.5-2.4;   25-130 mg/L at pH 1.82-3.10; 25°C –1268.72; –1267.1
Arseniosiderite Ca2Fe3O2(AsO4)3•3H2O Monoclinic 3.1-27 mg/L at pH 6.85-8.15; 25°C -
Kaatialaite Fe(H2AsO4)3•5(H2O) Monoclinic 5.4 g/L; TCLPbtest -
Kaňkite Fe3(AsO4)•3.5H2O Monoclinic - -
Kolfanite Ca2Fe3O2(AsO4)3 •2H2O Monoclinic 1.36 mg/L at pH 8; 20°C -
Parasymplesite Fe3(AsO4)•8H2O Monoclinic - -
Pharmacosiderite K[Fe4(OH)4(AsO4)3]•6.5H2O Cubic - -
Scorodite FeAsO4•2H2O Orthorombic 0.33-5.89 mg/L at pH 5.01-6.99; 22°C; 0.11-463 mg/L at pH 0.97-7.92; 23°C; 1.8-10.3 mg/L at pH 5.53-6.36; 25°C –1282.42; –1285.05; –1279.2; –1263.52
Symplesite Fe3( AsO4)2•8H2O Triclinic 0.024-7 mg/L at pH 6.0-9.1; 27°C –3751.02; –3792.01
Yukonite Ca7Fe12(AsO4)10(OH)20•15H2O Amorphous 1.16-5.11 at pH 7.56-8.82; 20°C; 6.3-51 mg/L at pH 5.5-6.15; 25°C -
Beudantite PbFe3(AsO4)(SO4)(OH)6 Hexagonal <0.02 mg/L at pH 4.3-4.65; 25°C –3055.6; –3081.12
Bukovskýite Fe2(AsO4)(SO4)(OH)•7H2O Triclinic - –3480
Sarmientite Fe2(AsO4)(SO4)(OH)•5H2O Monoclinic - -
Tooeleite Fe6(AsO3)4(SO4)(OH)4•4H2O Monoclinic - -
Zýkaite Fe4(AsO4)3(SO4)(OH)•15H2O Orthorombic - -
Haidingerite Ca(AsO3OH)•H2O Orthorombic 2050 mg/L at pH 6.22; 23°C 3120–4360   mg/L   at pH 4.93; TCLPb test –1533
Hӧrnesite Mg3(AsO4)2•8H2O Monoclinic 300-1100 mg/L at pH 6.5-7.4 -
Pharmacolite Ca(HAsO4)•2H2O Monoclinic 5919 mg/L at pH 6.7; 25°C 3120-4360   mg/L at pH 4.93; TCLPb test –1808.21
Picropharmacolite Ca4Mg(AsO4)2(HAsO3OH)2•11H2O Triclinic - -
Weilite CaHAsO4 Triclinic 2170-3610   mg/L   at pH 4.93; TCLPb test 540-764  mg/L at  Ph 3-8; 35°C –1292.48
Adamite Zn2(AsO4)(OH)   - –1252.29
Annabergite Ni3(AsO4)2•8H2O Orthorombic 47.8-1449 mg/L at pH 3-9; 22°C –3488.57; –3482.34
Austinite CaZn(AsO4)(OH) Orthorombic - –1651.13
Bayldonite PbCu3(AsO4)2(OH)2 Triclinic - –1810.6
Clinoclase Cu3(AsO4)(OH)3 Monoclinic - –1209.48
Conichalcite CaCu(AsO4)(OH) Orthorombic - –1470.17
Cornubite Cu5(AsO4)2(OH)4 Triclinic - –2057.9
Duftite PbCu(AsO4)(OH) Orthorombic - –959.92
Erythrite Co3(AsO4)2•8H2O Monoclinic - -
Euchroite Cu2(AsO4)(OH)•3(H2O) Orthorombic - –1552.7
Fornacite Pb2Cu(AsO4)(CrO4)(OH) Monoclinic 0.03 mg/L at pH 6.96 –1956.86l
Kӧttigite Zn3(AsO4)2•8H2O Monoclinic 16 mg/L at pH 4.87 –4030.48
Legrandite Zn2(AsO4)(OH)•H2O Monoclinic - –1488.6
Mansfieldite AlAsO4•2H2O Orthorombic - –1730.78; –1720.8
Mimetite Pb5(AsO4)3Cl Hexagonal - –2675.5; –2616.8
Olivenite Cu2(AsO4)(OH) Monoclinic - –845.52
Schultenite Pb(AsO3OH) Monoclinic 8.8 mg/L at pH 4.68; 25°C –805.66; –809.62
Sterlinghillite Mn3(AsO4)2•4H2O Monoclinic - –4045.17
Arsenopyrite FeAsS Monoclinic - -141.6
α,Realgar AsS Monoclinic - -31.3
β,Realgar AsS Monoclinic - -30.9
α,Orpiment As2O3   - -84.9
am, Orpiment As2O3 Monoclinic - -76.8
a.: pH and total arsenic solubility values are the highest and lowest levels presented and there is no relation between solubility and pH values.
b.: TCLP means Toxicity Characteristic Leaching Procedure.
Table 2: Arsenic minerals formula, crystal system, ΔfG° and solubility for standard state conditions, 298.15 K and 1 atm; adopted and modified from [27,30,31].