The sulphides of arsenic, antimony, and bismuth

The sulphides of arsenic, antimony, and bismuth These elements form the following sulphides  

Bismuth does not form a pentasulphide the structures of AS2S5 and Sb2Ss are not known. 

The double chains in SbjSa (diagiammatic). The laigei circles represent S atoms. All the atoms of one chain ate shaded, and the weak secondary Sb-S bonos are shown as broken lines. 

A simple chain with the composition M2 S3 for an element M forming three bonds is 

There are also mixed compounds containing Cg rings and, for example, aliphatic side chains. 

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