Synthesis of Au2S and Au2S3 Using H2S, Short-Chain and Ring-Structured Sulfur as Sulfur Sources

To determine which of the two known gold sulfides (containing either monoor trivalent gold) are formed by reacting trivalent gold with differnt allotropes o f sulfur, experiments were made using three different sources of sulfur. When trivalent gold in the form of A u 2 ( S 0 4 ) 3 in concen­ trated acid is reacted with electrolytically formed short-chain sulfur, monovalent gold sulfide (A u 2S) is formed. If hydrogen sulfide gas reacts with the same solution, trivalent gold sulfide (A u 2S3) is produced. Alternatively, if ordinary a-sulfur (ring structure) is used, a 50/50 mixture of Au2S and A u 2 S3 is formed. The synthesis procedure for the two gold sulfides is substantially simpler than previously reported methods of preparation.