Potassium sulfide 5067669 219267520 2008-06-14T11:46:36Z Puppy8800 5404759 iw {{Chembox new | Name = Potassium sulfide | ImageFile = Potassium-sulfide-unit-cell-3D-ionic.png <!-- | ImageSize = 200px --> | ImageName = Potassium sulfide | IUPACName = Potassium sulfide | OtherNames = Dipotassium monosulfide,<br />Dipotassium sulfide,<br />Potassium monosulfide | Section1 = {{Chembox Identifiers | CASNo = 1312-73-8 | RTECS = TT6000000 }} | Section2 = {{Chembox Properties | Formula = K<sub>2</sub>S | MolarMass = 110.262 g/mol | Appearance = pure: colourless<br />impure: yellow-brown | Density = 1.8 g/cm<sup>3</sup> | Solubility = converts to KSH, KOH | Solvent = other solvents | SolubleOther = soluble in [[ethanol]] and [[glycerol]] | MeltingPt = 840 °C }}<!-- |[[Boiling point]] | ? °C |- --> | Section3 = {{Chembox Structure | CrystalStruct = anti[[Fluorite]] }} | Section7 = {{Chembox Hazards | ExternalMSDS = | MainHazards = toxic | RPhrases = 31-34 | SPhrases = 26-45 }} | Section8 = {{Chembox Related | OtherCpds = [[Sodium sulfide|Na<sub>2</sub>S]] }} }} '''Potassium sulfide''' is the [[chemical compound]] with the formula K<sub>2</sub>S. It is an inorganic polymer with the "antifluorite structure," which means that the small K<sup>+</sup> ions occupy the tetrahedral (F<sup>−</sup>) sites in [[fluorite]], and the larger S<sup>2−</sup> centers occupy the eight-coordinate (Ca<sup>2+</sup>) sites. [[lithium sulfide|Li<sub>2</sub>S]], [[sodium sulfide|Na<sub>2</sub>S]], and Rb<sub>2</sub>S crystallize similarly.<ref name=Holleman>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> This salt contains the highly basic anion S<sup>2−</sup>, which completely [[hydrolysis|hydrolyzes]] in water according to the following equation: :K<sub>2</sub>S + H<sub>2</sub>O → KOH + KSH For many purposes, this reaction is inconsequential since the mixture of SH<sup>−</sup> and OH<sup>−</sup> behaves as a source of S<sup>2−</sup>. Other alkali metal sulfides behave similarly.<ref name=Holleman/> K<sub>2</sub>S arises from the reaction of potassium and sulfur. In the laboratory, this synthesis is usually conducted in a solution of anhydrous ammonia. ==Sulfurated potash (“Liver of Sulfur”)== '''Sulfurated potash''' is a poorly defined mixture of potassium sulfide, potassium [[polysulfide]], [[thiosulfate|potassium thiosulfate]], and probably potassium [[bisulfide]]. Synonyms include hepar sulfuris''', '''Liver of sulfur, sulfurated potash, sulfurated potassa. Liver of sulfur is mainly used in metalworking to form a [[patina]], turning [[copper]] [[alloys]] brown. Liver of sulfur was once used in pharmaceutical preparations such as “white lotion”. At one time sulfurated potash was used to combat [[arthritis]]. It is not surprising that it fell into disfavor because sulfides and polysulfides are toxic. 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. The compound is not added directly to the fireworks but rather forms during their combustion<ref name=Shimizu>Shimizu, Takeo. "Fireworks: the Art, Science, and Technique." Pyrotechnica Publications: Austin, 1981. ISBN 0-929388-05-4.</ref>. ==References== {{reflist}} [[Category:Potassium compounds]] [[Category:Sulfides]] [[Category:Inorganic compounds]] [[ar:كبريتيد بوتاسيوم]] [[ca:Sulfur de potassi]] [[de:Kaliumsulfid]] [[pl:Siarczek potasu]] [[zh:硫化钾]]