Potassium sulfide
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Names | |
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IUPAC name
Potassium sulfide
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Other names
Dipotassium monosulfide,
Dipotassium sulfide, Potassium monosulfide, Potassium sulfide |
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Identifiers | |
1312-73-8 ![]() |
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3D model (Jmol) | Interactive image |
ECHA InfoCard | 100.013.816 |
RTECS number | TT6000000 |
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Properties | |
K2S | |
Molar mass | 110.262 g/mol |
Appearance | pure: colourless impure: yellow-brown |
Odor | HS |
Density | 1.74 g/cm3 |
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 |
−60.0·10−6 cm3/mol | |
Structure | |
antiFluorite | |
Hazards | |
Main hazards | Dangerous for the environment (N) |
R-phrases | R17, R23, R25, R31, R34, R50 |
S-phrases | S24, S26 |
Related compounds | |
Other cations
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Sodium sulfide, Iron(II) sulfide |
Related compounds
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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).
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Infobox references | |
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.
Structure[edit]
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.[1]
Synthesis and reactions[edit]
It can be produced by heating K2SO4 with carbon (coke):
- K2SO4 + 4 C → K2S + 4 CO
In the laboratory, pure K2S may be prepared by the reaction of potassium and sulfur in anhydrous ammonia. [2]
Sulfide is highly basic, consequently K2S completely and irreversibly hydrolyzes in water according to the following equation:
- K2S + H2O → KOH + KSH
For many purposes, this reaction is inconsequential since the mixture of SH− and OH− behaves as a source of S2−. Other alkali metal sulfides behave similarly.[1]
Use in fireworks[edit]
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.[3]
See also[edit]
References[edit]
- ^ a b 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.