Gallium(III) oxalate is an inorganic compound of gallium and the oxalate ion, with the formula Ga2(C2O4)3. It is a white solid that is only slightly soluble in water.
Preparation Hydrated gallium(III) oxalate can be prepared by reacting an aqueous gallium(III) salt with oxalic acid. A tetrahydrate has been reported from hot solutions of gallium nitrate and oxalic acid.
Properties Solubility and complex formation Gallium(III) oxalate is sparingly soluble in water.
Gallium(III) also forms soluble oxalato complexes in solution. Species such as [Ga(C2O4)2]− and [Ga(C2O4)3]3− have been reported, and gallium generally has a greater tendency than aluminium to form such oxalate complexes.
Hydrothermal decomposition Under hydrothermal conditions, gallium oxalate can decompose to gallium oxide hydroxide, GaOOH. Treatment at about 175 °C has been used to produce α-GaOOH, with the oxalate acting as the gallium precursor.
The overall conversion may be represented as:
Ga2(C2O4)3 + H2O → 2 GaOOH + 2 CO2 + 4 CO
Further heating of GaOOH gives gallium oxide.
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