Gold(III) sulfide

Gold(III) sulfide or auric sulfide is an inorganic compound with the formula Au2S3. Auric sulfide has been described as a black and amorphous solid. Only the amorphous phase has been produced, and the only evidence of existence is based on thermal analysis.

Claims
Early investigations claimed to prepare auric sulfide by the reaction of lithium tetrachloroaurate with hydrogen sulfide:
 * 2 Li[AuCl4] + 3 H2S → Au2S3 + 2 LiCl + 6 HCl

Similar preparations via chloroauric acid, auric chloride, or gold(III) sulfate a claimed proceed in anhydrous solvents, but water evinces a redox decomposition into metallic gold in sulfuric acid:
 * 8 Au(3+) + 3 S(2-) + 12 H2O → 8 Au + 3 H2SO4 + 18 H+

Conversely, it is claimed that cyclo-octasulfur reduces gold(III) sulfate to a mixture of gold sulfides and sulfur oxides:
 * Au2(SO4)3 + S8 → Au2S3 + Au2S + 4 SO3 + 6 SO2

Auric sulfide has also been claimed as the product when auric acetate is sonicated with cyclo-octasulfur in decalin.

Auric sulfide is claimed to react with nitric acid as well sodium cyanide. It is claimed to dissolve in concentrated sodium sulfide solution.