| This compound is extremely soluble in water and three hydrates are known. The hydrate 2Al2O3(SiO2.12WO3)3.93H2O crystallises in regular octahedra; the hydrate with 87H2O crystallises in rhombohedra (a:c = 1:2.6653); and the hydrate with 60H2O forms triclinic crystals (a:b:c = 0.8563:1:1.0658; α = 87°44', β = 105°11', γ = 91°48'). The first two salts are therefore isomorphous with the corresponding gallium salts. |