Potassium sulfide

title: "Potassium sulfide" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["potassium-compounds", "sulfides", "inorganic-compounds", "fluorite-crystal-structure"] topic_path: "general/potassium-compounds" source: "https://en.wikipedia.org/wiki/Potassium_sulfide" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
| Watchedfields = changed | verifiedrevid = 434168427 | Name = Potassium sulfide | ImageFile = Potassium-sulfide-unit-cell-3D-ionic.png | ImageName = Potassium sulfide | ImageFile1 = Potassium sulfide.JPG | IUPACName = Potassium sulfide | OtherNames = Dipotassium monosulfide, Dipotassium sulfide, Potassium monosulfide, Potassium sulfide |Section1={{Chembox Identifiers | CASNo_Ref = | CASNo = 1312-73-8 | UNII_Ref = | UNII = 31R0R7HD0N | RTECS = TT6000000 | EC_number = 215-197-0 | UNNumber = 1847 1382 | PubChem = 162263 | ChemSpiderID = 142491 | SMILES = [S-2].[K+].[K+] | StdInChI = 1S/2K.S/q2*+1;-2 | StdInChIKey = DPLVEEXVKBWGHE-UHFFFAOYSA-N
|Section2={{Chembox Properties | Formula = K2S | MolarMass = 110.262 g/mol | Appearance = pure: colourless impure: yellow-brown | Odor = H2S | Density = 1.74 g/cm3 | Solubility = converts to KSH, KOH | Solvent = other solvents | SolubleOther = soluble in ethanol, glycerol insoluble in ether | MeltingPtC = 840 | BoilingPtC = 912 | BoilingPt_notes = (decomposes) | MagSus = −60.0·10−6 cm3/mol |Section3={{Chembox Structure | CrystalStruct = antifluorite |Section4={{Chembox Thermochemistry |DeltaHf=−406.2 kJ·mol−1 |DeltaGf=−392.4 kJ·mol |Entropy=105.00 J·mol−1·K−1 |Section7={{Chembox Hazards | ExternalSDS = | MainHazards = Causes skin burns. Dangerous for the environment | GHSPictograms = | GHSSignalWord = Danger | HPhrases = | PPhrases =
|Section8={{Chembox Related | OtherAnions = Potassium oxide Potassium selenide Potassium telluride Potassium polonide | OtherCations = Lithium sulfide Sodium sulfide Rubidium sulfide Caesium sulfide | OtherCompounds = Potassium hydrosulfide Potassium sulfite Potassium sulfate Iron(II) sulfide ::figure[src="https://upload.wikimedia.org/wikipedia/commons/1/12/Сульфид_калия.jpg" caption="Powdered potassium sulfide anhydrous" alt="Potassium sulfide"] ::
Potassium sulfide is an 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
It adopts an 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
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.
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.
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.
References
References
- (1981). "The standard enthalpy of formation of potassium sulfide (K2S) by fluorine bomb calorimetry". The Journal of Chemical Thermodynamics.
- (2014). "CRC Handbook of Chemistry and Physics". CRC Press.
- 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.
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