| IUPAC name
| Other names
|3D model (Jmol)||Interactive image|
|Molar mass||110.262 g/mol|
|Appearance|| pure: colourless|
|Melting point||840 °C (1,540 °F; 1,110 K)|
|Boiling point||912 °C (1,674 °F; 1,185 K) (decomposes)|
|converts to KSH, KOH|
|Solubility in other solvents|| soluble in ethanol, glycerol |
insoluble in ether
|Main hazards||Dangerous for the environment (N)|
|R-phrases||R17, R23, R25, R31, R34, R50|
|Sodium sulfide, Iron(II) sulfide|
|Potassium hydrosulfide, Potassium sulfite, Potassium sulfate|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|(what is ?)|
Potassium sulfide is the inorganic compound with the formula K2S. The colourless solid is rarely encountered, because it reacts readily with water, a reaction that affords potassium hydrosulfide (KSH) and potassium hydroxide (KOH). Most commonly, the term potassium sulfide refers loosely to this mixture, not the anhydrous solid.
It adopts "antifluorite structure," which means that the small K+ ions occupy the tetrahedral (F−) sites in fluorite, and the larger S2− centers occupy the eight-coordinate sites. Li2S, Na2S, and Rb2S crystallize similarly.
Synthesis and reactions
- K2SO4 + 4 C → K2S + 4 CO
Sulfide is highly basic, consequently K2S completely and irreversibly hydrolyzes in water according to the following equation:
- K2S + H2O → KOH + KSH
Use in fireworks
Potassium sulfides are formed when black powder is burned and are important intermediates in many pyrotechnic effects, such as senko hanabi and some glitter formulations.
- Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 360.
- Shimizu, Takeo. "Fireworks: the Art, Science, and Technique." Pyrotechnica Publications: Austin, 1981. ISBN 0-929388-05-4.