Synthesis and Structure of (NH4)2[(AuI4)(MI4)] (M = Ga,In)

The compounds (NH₄)₂(AuI₄)(MI₄)] (M = Ga, In) were obtained in sealed glass ampoules by reaction of I₂, NH₄I, Au and Ga or In as air‐sensitive black crystals. Both compounds crystallize in the orthorhombic space group Pnma (No. 62) and are isotypic: (NH₄)₂(AuI₄)(GaI₄)], a = 12.619(2), b = 20.625(5) and c = 7.693(2) Å; (NH₄)₂(AuI₄)(InI₄)], a = 12.587(2), b = 20.606(5) and c = 7.696(2) Å. The structures can be described as constituted of NH₄⁺ cations and anionic zig zag chains of alternating tetrahedral MI₄^– (M = In, Ga) and square planar AuI₄^– units running along 010]. Within the chains, the MI₄^– ions form weak interactions with two of their I atoms to the AuI₄^– ions resulting in strongly elongated AuI₆ octahedra.