Polysulfide Ions and Solutions

Free polysulfide ions consist of sulfur chains. The atoms of an chain are necessarily coplanar. Longer chains, however, exhibit different possibilities of isomerism. For example, by addition of one sulfur atom d- and can be obtained (Fig. 1). To describe the structxures, in 

The chain derives from the 84 one by addition of one more sulfur atom, so that the dihedral angle of 90° is maintained. In doing so, we obtain structures c and d (Fig. 1), the cis and (d and /) trans forms of the 85 chain. 8imilarly, by further addition of one sulfur atom, it can be shown that for an 8g chain three (enantiomorphic) isomers will result (cis,cis trans,trans and cis,trans, each d and /, respectively). The cis-Si and cis,cis-S ions may be regarded as parts of the 8g ring 

Solutions containing several species (but mainly 84 and 85 ) are obtained upon digesting sulfur with aqueous sulfide. Solutions in methanol and ethanol may be prepared correspondingly. Salts of S (n = 2-8) can be obtained not only from such solutions but also from liquid NHj and in dry reactions. 

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