[4] H2S2 is colourless, higher members are yellow with the colour increasing with the sulfur content.
To suppress this behavior, containers for polysulfanes are often pretreated with acid to remove traces of alkali.
[6] In contrast to the thermodynamic instability of polysulfates, polysulfide anions form spontaneously by treatment of S2− with elemental sulfur: Beyond H2S and H2S2, many higher polysulfanes H2Sn (n = 3 – 8) are known.
[6] They also react with sulfite and cyanide producing thiosulfate and thiocyanate respectively.
Other more selective syntheses are: The reaction of polysulfanes with sulfur dichloride or disulfur dichloride produces long-chain dichloropolysulfanes: The reaction with a sulfite salt (a base) quantitatively decomposes the polysulfane to produce thiosulfate and hydrogen sulfide: