Potassium hydrogen sulphide, KSH

The Potassium hydrogen sulphide, KSH can be obtained by the action of hydrogen sulphide on potassium suspended in ether. It can also be prepared by saturating an aqueous solution of potassium hydroxide with hydrogen sulphide, evaporating to dryness in vacuum, and eliminating the water from the resulting ¼-hydrate or ½-hydrate by a current of dry hydrogen. It can be precipitated quantitatively by adding benzene or ether to a solution of sodium ethoxide in absolute alcohol saturated with hydrogen sulphide -

C₂H₅ONa + H₂S = NaSH + C₂H₅OH.

Potassium hydrogen sulphide forms white, miscroscopic cubes, more deliquescent than the corresponding sodium derivative. The heat of formation from the element is given as 64.0 Cal., and that in aqueous solution as 65.1 Cal.