7675. Potassium Sulfide

Nomenclature

CAS number: 1312-73-8
Potassium monosulfide.
K2S; mol wt 110.26.
K 70.92%, S 29.08%.

Description and references

Best prepd from the elements in liq ammonia: Klemm et al., Z. Anorg. Allg. Chem. 241, 281 (1939); Feher in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 360-361.

Properties

White, cubic crystals or fused plates. Discolors in air. Very hygroscopic. Unstable. Spontaneously combustible on percussion or rapid heating. d 1.74. mp 912°. Freely sol in water. Aq solns are strongly alkaline.

Derivative

Pentahydrate.

Properties

Colorless rhombs. Odor of hydrogen sulfide. Discolors upon exposure to light and air (yellow to yellowish red). mp 60°. Spontaneously combustible. Freely sol in water, alc, glycerol. Insol in ether. Densities of aq solutions at 25° (calcd as % K2S.5H2O): 1.82%: 1.009; 10.90%: 1.049; 21.80%: 1.100; 29.07%: 1.136; 39.97%: 1.192; 50.88%: 1.250; 81.77%: 1.432. Aq solns are very caustic and prone to decompn. See the hydrolysis reactions under Sodium Sulfide.