Auric nitrates

Complex derivatives with the anion Au(NO₃)₄' are known. Auric hydroxide and nitric acid yield a substance of the formula HAu(NO₃)₄,3H₂O, crystallizing in octahedra, and soluble in concentrated nitric acid. Aurinitric acid melts at 72° to 73° C., and its density is 2.84. When heated above its melting-point, it is converted into a black substance, possibly auric nitrate, Au(NO₃)₄. Aurinitrates of rubidium, potassium, thallium, and ammonium have been prepared. From the ammonium salts a yellowish-brown, explosive substance, similar in properties to fulminating gold, has been obtained. Several basic nitrates of gold are also known.