ABSTRACT
If sulfur is compared with its neighbours, oxygen and chlorine, we can see that it has a much greater potential to form extended arrays of -S-S-S-links. Chlorine, with one electron more, has a fully satisfied electron configuration in diatomic CI-CI, and the halogens only form longer chains to a limited extent, with weaker interactions, and mainly involving iodine (compare Tables 17.19 and 17.20, and Fig. 17.59). Oxygen differs from S in its ability to form a stable double bond in 0=O, and species with 0^ chains readily break up with formation of 0=0. Thus polyoxygen species are limited to n — 3 and 4 (Section 17.7.1). In contrast, sulfur has one electron less than Cl, and any S=S is unstable with respect to -S-S-, encouraging chain formation. The S2 molecule does occur in the gas at high temperatures and gives a purple, paramagnetic solid on rapid cooling, but it reverts to S8 when allowed to warm to room temperature.
