Tungsten trisulfide
{{Chembox
|OtherNames = Tungsten(VI) sulphide, tris(sulfanylidene)tungsten
|Section1={{Chembox Identifiers
|CASNo = 12125-19-8
|ChemSpiderID = 9215149
|EINECS = 235-734-2
|PubChem = 11039977
|StdInChI = 1S/3S.W
|StdInChIKey = YMZATHYBBBKECM-UHFFFAOYSA-N
|SMILES = S=[W](=S)=S
}}
|Section2={{Chembox Properties
|Formula = WS3
|MolarMass = 280.038 g/mol
|Appearance = Brown solid
}}
|Section3={{Chembox Related
|OtherCompounds = Tungsten disulfide
}}
}}
Tungsten trisulfide is an inorganic compound of tungsten and sulfur with the chemical formula WS3.{{cite journal |last1=Scott |first1=Robert A. |last2=Jacobson |first2=Allan J. |last3=Chianelli |first3=Russ R. |last4=Pan |first4=W. H. |last5=Stiefel |first5=Edward I. |last6=Hodgson |first6=Keith O. |last7=Cramer |first7=Stephen P. |title=Reactions of molybdenum trisulfide, tungsten trisulfide, tungsten triselenide, and niobium triselenide with lithium. Metal cluster rearrangement revealed by EXAFS |journal=Inorganic Chemistry |date=1 April 1986 |volume=25 |issue=9 |pages=1461–1466 |doi=10.1021/ic00229a032 |url=https://pubs.acs.org/doi/abs/10.1021/ic00229a032 |access-date=1 November 2021 |issn=0020-1669}}{{cite book |last1=Hille |first1=Russ |last2=Schulzke |first2=Carola |last3=Kirk |first3=Martin L. |title=Molybdenum and Tungsten Enzymes: Bioinorganic Chemistry |date=29 September 2016 |publisher=Royal Society of Chemistry |isbn=978-1-78262-877-4 |page=155 |url=https://books.google.com/books?id=FRU0DQAAQBAJ&dq=Tungsten+trisulfide&pg=PA155 |access-date=1 November 2021 |language=en}} The compound looks like chocolate-brown powder.{{cite web |title=Tungsten trisulfide |url=https://webbook.nist.gov/cgi/formula?ID=B8025276 |publisher=National Institute of Standards and Technology|access-date=1 November 2021 |language=en}}
Synthesis
1. Bubbling hydrogen sulfide through hot acidified solution of tungstenates.{{cite book|first1=A. N.|last1=Zelikman|first2=O. E.|last2=Krein|first3=G. V.|last3=Samsonov|trans-title=Metallurgy of Rare Metals|title=Metallurgiya redkikh metallov|edition=2nd|editor-first=L. V.|editor-last=Belyaevskaya|orig-date=1964|publisher=S. Monson / Wiener Bindery|series=Israel Program for Scientific Translations|location=Jerusalem|year=1966|translator-first=A.|translator-last=Aladjem |page=7 |url=https://books.google.com/books?id=zUwjAAAAMAAJ |access-date=1 November 2021 |via=Google Books}}
2. Reaction of tungsten disulfide and elemental sulfur on heating:{{cite web |title=Tungsten Trisulfide-- Tungsten Trisulfide Professional Manufacturer and Supplier |url=http://www.tungsten-powder.com/tungsten-trisulfide.html |publisher=tungsten-powder.com |access-date=1 November 2021}}
:{{chem2 | WS2 + S -> WS3 }}
3. Precipitates upon acidification of thiotungstate solutions:
:{{chem2 | (NH4)2WS4 + HCl -> WS3 + 2 NH4Cl + H2S }}
:{{chem2 | Na2WS4 + H2SO4 -> WS3 + Na2SO4 + H2S }}
Physical properties
Slightly soluble in cold water and forms colloidal solution in hot water.
Soluble in alkali metal carbonates and alkali metal hydroxides.{{cite book |title=Kirk-Othmer Concise Encyclopedia of Chemical Technology, 2 Volume Set |date=16 July 2007 |publisher=John Wiley & Sons |isbn=978-0-470-04748-4 |page=1122 |url=https://books.google.com/books?id=BYQfEAAAQBAJ&dq=Tungsten+trisulfide&pg=RA1-PA1122 |access-date=1 November 2021 |language=en}}
Chemical properties
Tungsten trisulfide can be decomposed by heating into tungsten disulfide and elemental sulfur:
:{{chem2 | WS3 -> WS2 + S }}
Reacts with sulfide solutions:
:{{chem2 | WS3 + (NH4)2S -> (NH4)2WS4 }}
Reduced by hydrogen:
:{{chem2 | WS3 + 3H2 -> W + 3 H2S }}