Preparation of sulfides

Most metals react directly with sulfur to form metail sulfides—i.e., compounds that contain a metal atom and the sulfide ion, S²⁻. In addition to direct combination of the elements as a method of preparing sulfides, they can also be produced by reduction of a sulfate by carbon or by precipitation from acidic aqueous solution by hydrogen sulfide, H₂S, or from basic solution by ammonium sulfide, (NH₄)₂S. Another method, particularly suitable for water-soluble sulfides, involves bubbling H₂S into a basic solution of the metal to give the metal hydrogen sulfide, MHS. A further equivalent of metal hydroxide added will yield the metal sulfide.NaOH + H₂S → NaHS + H₂O
NaHS + NaOH → Na₂S + H₂O