: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 = −88.8·10−6 cm3/mol
}}
|Section3={{Chembox Structure
| CrystalStruct = Trigonal, hR81
| SpaceGroup = R3, No. 146
| LattConst_a = 12.150(2) Å
| LattConst_c = 18.190(4) Å
| UnitCellVolume = 2325.57 Å3
| UnitCellFormulas = 27
}}
|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{{cite web| publisher = webmineral| url = http://webmineral.com/data/Carlinite.shtml| access-date = 2009-06-06| title =Carlinite}} 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.{{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 }}
Synthesis
Tl2S can be prepared from the elements or by precipitating the sulfide from a solution of thallium(I), e.g. the 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 {{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 }}
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,{{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}} 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.{{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}} Cashman's work culminated in the development of long wave infrared detectors used during the Second World War.American patent 2448517, filed 1944, granted 1948 Reliable Tl2S detectors were also developed in Germany at the same time.