Potassium Sulfide

(redirected from Potassium sulphide)

potassium sulfide

[pə′tas·ē·əm ′səl‚fīd]
(inorganic chemistry)
K2S Moderately flammable, water-soluble, deliquescent red crystals; melts at 840°C; used in analytical chemistry, medicine, and depilatories. Also known as fused potassium sulfide; hepar sulfuris; potassium sulfuret.

Potassium Sulfide

 

K2S, a salt; colorless crystals. Density, 1.80 g/cm3; melting point, 471°C.

Potassium sulfide is hygroscopic and highly water-soluble. It readily oxidizes on exposure to atmospheric oxygen to potassium thiosulfate, K2S2O3. Boiling aqueous potassium sulfide with excess sulfur forms the potassium polysulfides K2S2, K2S3, K2S4, K2S5, and K2S6. Potassium sulfide is obtained by the reactions:

KOH + H2S = KHS + H2O

and KHS + KOH = K2S + H2O

The fusion of potash with sulfur results in the formation of sulfurated potash, a mixture of potassium polysulfides and thiosulfates, which is used in the preparation of sulfur baths. Potassium sulfide is also used in photography.

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