Potassium mono-sulfide

Sulfur can be introduced into a diazonium salt by the SN1 reaction shown in Figure 5.51. In order to prevent the reagent from effecting a double (rather than a mono-) arylation at the sulfur atom, potassium xanthogenate instead of sodium sulfide is used as the sulfur nucleophile. The resulting S-aryl xanthogenate C is hydrolyzed. In this way diarylsulfide-free aryl thiol B is obtained. 

Table 3-2 and Figure 3-2 describe the health effects observed in humans and experimental animals associated with dose and duration of oral exposure to selenium and selenium compounds (i.e., elemental selenium dust, selenium dioxide dissolved in water [selenious acid], sodium selenate, sodium selenite, potassium selenate, and dietary selenium compounds, which include selenoamino acids). All doses for these compounds are expressed in terms of total selenium. Table 3-3 and Figure 3-3 describe health effects observed in laboratory animals following oral exposure to selenium sulfides (SeS2 and SeS) at varying doses and exposure durations. All doses for selenium sulfide compounds are expressed in terms of the compound, because selenium sulfide preparations often exist as a variable mixture of the mono-and disulfide forms, precluding accurate expression of the dose in terms of total selenium. 

We would expect potassium sulfide melts to be formed from mono- and diatomic sulfur gas, primarily the diatomic gas, and the even numbered polythio ions or the monosulfide. Since the tetrasulfide decomposes at 850°C and higher sulfide numbers are associated with lower decomposition temperatures, their role in the chemistry discussed here is very short lived if it exists. We are reduced to dipotassium monosulfide, dipotassium disulfide and dipotassium tetrasulfide as possible sulfide species. Similarly, the possible thio-oxo ions are eliminated except for sulfate others may have fleeting existence but if the temperatures at which they are known to... 

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