Thallium(I) sulfide

{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 470605697 | ImageFile = Thallium(I)-sulfid.png | ImageSize = 240px | ImageCaption = Unit cell of thallium sulfide. | ImageAlt = Unit cell of thallium sulfide under standard conditions. The yellow atoms represent the sulfur anions. | IUPACName = Thallium(I) sulfide | OtherNames = thallous sulfide, thallous sulphide |Section1={{Chembox Identifiers | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 1314-97-2 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = W63QXT8PYG | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/S.2Tl/q-2;2*+1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = BXJGLLKRUQQYTC-UHFFFAOYSA-N | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 140161 | SMILES = S([Tl])[Tl] | PubChem = 16683485 | EINECS = 215-250-8 }} |Section2={{Chembox Properties | Formula = Tl₂S | MolarMass = 440.833 g/mol | Appearance = black crystalline solid | Density = 8.390 g/cm³ | MeltingPtC = 448 | BoilingPtC = 1367 | Solubility = | MagSus = &minus;88.8·10⁻⁶ cm³/mol }} |Section3={{Chembox Structure | CrystalStruct = [[Trigonal]], [[Pearson symbol|hR81]] | SpaceGroup = R3, No. 146 | LattConst_a = 12.150(2) Å | LattConst_c = 18.190(4) Å | UnitCellVolume = 2325.57 ų | UnitCellFormulas = 27 | LattConst_ref = <ref>{{Cite journal | doi=10.1006/jssc.2002.9711| title=Tl₂S: Re-Determination of Crystal Structure and Stereochemical Discussion| journal=Journal of Solid State Chemistry| volume=168| issue=1| pages=322–330| year=2002| last1=Giester| first1=G.| last2=Lengauer| first2=C.L.| last3=Tillmanns| first3=E.| last4=Zemann| first4=J.| bibcode=2002JSSCh.168..322G}}</ref> }} |Section7={{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}

'''Thallium(I) sulfide''', Tl₂S, is a chemical compound of [[thallium]] and [[sulfur]].

== Occurrence == Tl₂S is found in nature as the mineral carlinite<ref>{{cite web| publisher = webmineral| url = http://webmineral.com/data/Carlinite.shtml| access-date = 2009-06-06| title =Carlinite}}</ref> which has the distinction of being the only sulfide mineral of thallium that does not contain at least two metals. Tl₂S has a distorted anti-CdI₂ structure.<ref>{{cite journal| title = Tl₂S: Re-Determination of Crystal Structure and Stereochemical Discussion |first1 = G. |last1 =Giester|first2 = C. L. |last2 =Lengauer|first3 = E. |last3 =Tillmanns |first4 = J. |last4 =Zemann|author-link4 = Josef Zemann| journal = Journal of Solid State Chemistry| volume = 168| year =2002| issue = 1 | page =322 | doi = 10.1006/jssc.2002.9711|bibcode = 2002JSSCh.168..322G }}</ref>

== Synthesis == Tl₂S can be prepared from the elements or by precipitating the sulfide from a solution of thallium(I), e.g. the [[thallium(I) sulfate|sulfate]] or nitrate. Thin films have been deposited, produced from a mixture of citratothallium complex and thiourea. Heating the film in nitrogen at 300°C converts all the product into Tl₂S <ref>{{cite journal| title = Crystalline structure of chemically deposited thallium sulfide thin films| author = V. Estrella, M. T. S. Nair and P. K. Nair | journal = Thin Solid Films | volume = 414| year =2002| issue = 2| page = 281 | doi = 10.1016/S0040-6090(02)00500-X|bibcode = 2002TSF...414..281E }}</ref>

== History and applications == This salt was used in some of the earliest photo-electric detectors by [[Theodore Case]] who developed the so-called '''thalofide''' (sometimes spelt thallofide) cell, used in early film projectors. Case described the detector material as consisting of thallium, oxygen and sulfur,<ref>{{cite journal |author=T. W. Case |year=1920 |title=Thalofide Cell"—a New Photo-Electric Substance |journal=Phys. Rev. |volume=15 |issue=4 |page=289 |bibcode=1920PhRv...15..289C |doi=10.1103/PhysRev.15.289}}</ref> and this was incorrectly described by others as being thallium oxysulfide, which incidentally is a compound that is not known. Case's work was then built on by R.J. Cashman who recognised that the controlled oxidation of the Tl₂S film was key to the operation of the cell.<ref name="Lovell">{{cite journal |author=D. J. Lovell |year=1971 |title=Cashman thallous sulfide cell |journal=Appl. Opt. |volume=10 |issue=5 |pages=1003–8 |bibcode=1971ApOpt..10.1003L |doi=10.1364/AO.10.001003 |pmid=20094592}}</ref> Cashman's work culminated in the development of long wave infrared detectors used during the Second World War.<ref>American patent 2448517, filed 1944, granted 1948</ref> Reliable Tl₂S detectors were also developed in Germany at the same time.<ref name="Lovell" />

==References== {{reflist}}

{{Thallium compounds}} {{Sulfides}}

[[Category:Sulfides]] [[Category:Thallium(I) compounds]]