Auric bromide, AuBr₃

The Auric bromide, AuBr₃, is formed in aqueous solution by the action of water on gold dibromide. It can be obtained in the solid state from the same source by the action of moist ether, the aurous bromide formed remaining undissolved, and auric bromide being left on evaporation of the dried ether solution. It is also produced by the interaction of aqueous bromine and gold, as well as by the action of solutions of such perbromides as cobalt tribromide, manganese tetrabromide, and ferric bromide on the metal. The aqueous solution and the crystals deposited from it have a scarlet-red colour, but the pure salt contained from solution in ether is a dark-brown powder. At 160° C. it is completely transformed into aurous bromide in the form of a green mass, and bromine. When prepared by the action of bromine on precipitated gold, it forms black crystals, volatile in bromine at 300° C.