Iron(II) sulfide 2091630 209107716 2008-04-29T22:55:32Z Dasein45 7003186 added a "biology and biochemical uses" section {{Chembox new | Name = Iron(II) sulfide | ImageFile = Iron(II)-sulfide-sample.jpg <!-- | ImageSize = 200px --> | ImageName = Sample of iron(II) sulfide | ImageFile1 = Iron(II)-sulfide-unit-cell-3D-balls.png <!-- | ImageSize1 = 150px --> | ImageName1 = Ball-and-stick model of FeS's unit cell | OtherNames = Iron sulfide<br />Iron sulphide | Section1 = {{Chembox Identifiers | CASNo = 12068-85-8 }} | Section2 = {{Chembox Properties | Formula = FeS | MolarMass = 87.911 g/mol | Density = 4.84 g/cm<sup>3</sup> | Solvent = other solvents | SolubleOther = insoluble | MeltingPt = 1194 °C | BoilingPt = | Appearance = black solid}} }} '''Iron(II) sulfide''' is a [[chemical compound]] with the formula FeS. In practice, iron sulfides are often non-[[stoichiometric]]. Powdered iron sulfide is [[pyrophoric]]. FeS can be obtained by reacting [[iron]] and [[sulfur]]. :S<sub>8 (s)</sub> + 8Fe<sub>(s)</sub> → 8FeS<sub>(s)</sub> ==Forms of iron sulfide== "Iron sulfide" exists in several distinct forms which differ in the [[stoichiometry]] and properties: *[[Pyrrhotite]], Fe<sub>1-x</sub>S, a mineral as well as the waste product of the ''[[Desulfovibrionales|Desulfovibrio]]'' bacteria, pyrrhotite displays [[ferrimagnetism]]. *[[Troilite]], FeS, which has similar material to pyrrhotite, but does not possess [[ferromagnetic]] properties. *[[Mackinawite]], Fe<sub>1+x</sub>S, the least stable from of iron sulfide, mackinawite has a layered structure. *[[Pyrite]], mineral form of FeS<sub>2</sub> with a [[gold]]-like appearance, making it also known as "fool's gold." ==Pedagogical uses== Certain chemical principles are nicely illustrated using the chemistry of iron sulfides. The methods of [[chemical composition]] can be shown by the production of iron(II) sulfide from [[iron]] and [[sulfur]] (see equation above). *This reaction is [[exothermic]] as more energy is given out than taken in. *Iron shows [[ferromagnetism]]; iron sulfides do not. *Iron sulfide with [[hydrochloric acid]] (HCl), the [[acidic]] [[properties]] of hydrochloric acid and the pungent fume of [[hydrogen sulfide]] can both be demonstrated: :FeS<sub>(s)</sub> + 2HCl<sub>(aq)</sub> → FeCl<sub>2 (aq)</sub> + H<sub>2</sub>S<sub>(g)</sub> ==Biological and biochemical uses== The presence of ferrous sulfide as a visible black precipitate in the [[growth medium|growth medium]] [[peptone]] iron agar can be used to distinguish between [[microorganisms]] that produce the [[cysteine metabolism|cysteine metabolizing]] enzyme [[D-cysteine desulfhydrase|cysteine desulfhydrase]] and those that do not. Peptone iron agar contains the [[amino acid]] [[cysteine]] and a chemical indicator, [[ferric citrate]]. The [[catalysis]] of cysteine releases [[hydrogen sulfide]] gas that reacts with the ferric citrate to produce ferrous sulfide. ==See also== * [[Iron-sulfur world theory]] ==References== {{Citationstyle|date=September 2007}} <references/> *D. Vaughan, J. Craig, (1978) ''Mineral Chemistry of Metal Sulfides'', Cambridge University Press. ISBN 0-521-21489-0 [[Category:Iron compounds]] [[Category:Sulfides]] [[ar:كبريتيد حديد ثنائي]] [[de:Eisen(II)-sulfid]] [[ja:硫化鉄(II)]] [[pl:Siarczek żelaza(II)]] [[pt:Sulfeto de ferro]]