Potassium pentasulfide
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| Names | |
|---|---|
| Other names
Dipotassium pentasulfide, dipotassium sulphide, potassium polysulfide
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| Identifiers | |
3D model (JSmol)
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| Properties | |
| K2S5 | |
| Molar mass | 238.50 g·mol−1 |
| Appearance | red-orange prisms |
| Structure | |
| orthorhombic | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium pentasulfide is the inorganic compound with the formula K2S5. It is a red-orange solid that dissolves in water. The salt decomposes rapidly in air. It is one of several polysulfide salts with the general formula M2Sn, where M = Li, Na, K and n = 2, 3, 4, 5, 6.[1] The polysulfide salts of potassium and sodium are similar.
Preparation and reactions[edit]
The salt is prepared by the addition of elemental sulfur to potassium sulfide. An idealized equation is shown for potassium hydrosulfide:
- 4 KSH + S8 → 2 K2S5 + 2 H2S
The structure consists of zigzag chains of S2−5 paired with K+ ions.[2]
Occurrence[edit]
Various polysulfides K2S2 - K2S6 are components of liver of sulfur. Polysulfides, like sulfides, can induce stress corrosion cracking in carbon steel and stainless steel.
References[edit]
- ^ F. Fehér" Potassium Disulfide", "Potassium Tetrasulfide" "Potassium Pentasulfide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 361-367.
- ^ Barbara Kelly and Peter Woodward (1976). "Crystal structure of dipotassium pentasulphide". Journal of the Chemical Society, Dalton Transactions (14): 1314–1316. doi:10.1039/DT9760001314.