Sodium hydrogen sulphide, NaSH

When benzene or ether is added to a concentrated solution of sodium ethoxide in alcohol saturated with hydrogen sulphide, a quantitative yield of anhydrous sodium hydrogen sulphide is obtained:

C₂H₅ONa+H₂S = C₂H₅OH+NaSH.

It is a white, crystalline solid, very deliquescent, freely soluble in water, and moderately soluble in alcohol. When exposed to air it evolves hydrogen sulphide, and is completely decomposed by heat into this gas and sodium monosulphide. The anhydrous salt is also obtained by the interaction at 300° C. of sodium monosulphide and hydrogen sulphide free from carbon dioxide and oxygen. Sabatier's method is to saturate a solution of sodium sulphide with hydrogen sulphide, and concentrate in an atmosphere of the same gas. A solution can be obtained by saturating sodium-hydroxide solution with hydrogen sulphide. A dihydrate and a trihydrate have been described.

The heat of formation of the solid from the elements is given by Sabatier as 55.7 Cal.; that in solution by Thomsen as 58.48 Cal., and by Berthelot as 60.7 Cal. For the heat of solution of the anhydrous salt at 17.5° C. Sabatier gives 4.4 Cal., and for that of the dihydrate -1.5 Cal.; it follows that the heat of hydration of the dihydrate is 5.9 Cal.

The preparation in solution of a compound of the formula NaOSH has been described by Gutmann.