Tungsten trisulfide

Tungsten trisulfide is an inorganic compound of tungsten and sulfur with the chemical formula WS₃.^[1][2] The compound looks like chocolate-brown powder.^[3][4]

Tungsten trisulfide

Names
Other names Tungsten(VI) sulphide, tris(sulfanylidene)tungsten
Identifiers
CAS Number	12125-19-8
3D model (JSmol)	Interactive image
ChemSpider	9215149
EC Number	235-734-2
PubChem CID	11039977
InChI InChI=1S/3S.W Key: YMZATHYBBBKECM-UHFFFAOYSA-N
SMILES S=[W](=S)=S
Properties
Chemical formula	WS3
Molar mass	280.038 g/mol
Appearance	Brown solid
Related compounds
Related compounds	Tungsten disulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

1. Bubbling hydrogen sulfide through hot acidified solution of tungstenates.^[5]

2. Reaction of tungsten disulfide and elemental sulfur on heating:^[6]

WS₂ + S → WS₃

3. Precipitates upon acidification of thiotungstate solutions:^[5]

(NH₄)₂WS₄ + HCl → WS₃ + 2 NH₄Cl + H₂S

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.^[3]

Chemical properties

Tungsten trisulfide can be decomposed by heating into tungsten disulfide and elemental sulfur:

WS₃ → WS₂ + S

Reacts with sulfide solutions:

WS₃ + (NH₄)₂S → (NH₄)₂WS₄

Reduced by hydrogen:

WS₃ + 3H₂ → W + 3 H₂S