Sulfuric Acid → Gallium(III) sulfate hydrate

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Reaction Steps

4.1 g of gallium sulphate hydrate (the H2O/Ga2 (SO4)3 molar ratio is close to 25) are dissolved in 3.7 g of distilled water. The sulphate is obtained by dissolving gallium (Grade 1 from Johnson Matthey) in hot concentrated H2SO4, in excess, taking up the suspension obtained in ethanol at a concentration of 60% in water at normal temperature, reprecipitation, in this cooled solution, of gallium sulphate hydrate by adding ether followed by filtration and controlled drying. 1.15 g of 85% phosphoric acid (Prolabo) are added with stirring followed by 0.25 g of 40% hydrofluoric acid (Fluka) and, lastly, 4.55 g of di-n-propylamine (Fluka), abbreviated to DPA in what follows. Stirring is continued for approximately 15 minutes. The pH is then 6.

Provenance & Evidence