Can Sulfide exist in nature in an uncombined state?

Question

What is the chemical structure of Sulfide and how can in exist as S^2- ? Any help is much appreciated.

Answer 1

The term sulfide (sulphide in British English) refers to several types of chemical compounds containing sulfur in its lowest oxidation number of −2.

Formally, "sulfide" is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. Instead, sulfide combines with protons to form HS−, which is variously called hydrogen sulfide ion, hydrosulfide ion, sulfhydryl ion, or bisulfide ion. At still lower pH's (<7), HS− converts to H2S, hydrogen sulfide. Thus, the exact sulfur species obtained upon dissolving sulfide salts depends on the pH of the final solution.

Answer 2

No sulfides exist in a combine state with other substance.

Answer 3

Sulphide (British spelling) ions are simply the sulphur equivalent of oxide. Several natural suphides exist as important minerals and sources of metals. PbS as a mineral is called 'gallena' and is the main source of lead. Ditto sulphides of iron, zinc and tin.

Answer 4

no pure elements can be found naturally becaus the chemical are unbalanced

Answer 5

S2-, in the lab