Contents

Gallium(III) sulfide

Gallium(III) sulfide

Names
Other names gallium sesquisulfide
Identifiers
CAS Number	12024-22-5
3D model (JSmol)	Interactive image
ECHA InfoCard	100.031.526
EC Number	234-688-0
PubChem CID	165983
CompTox Dashboard (EPA)	DTXSID70904021
InChI InChI=1S/2Ga.3S/q2*+3;3*-2 Key: BVSHTEBQPBBCFT-UHFFFAOYSA-N
SMILES [S-2].[S-2].[S-2].[Ga+3].[Ga+3]
Properties
Chemical formula	Ga2S3
Molar mass	235.644 g/mol
Appearance	yellow (α-)
Density	3.77 g/cm3 [1]
Melting point	1,090 °C (1,990 °F; 1,360 K)[1]
Solubility in water	Reacts[2]
Magnetic susceptibility (χ)	−-80·10−6cm3/mol
Related compounds
Related compounds	Gallium(II) sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

Gallium(III) sulfide, Ga₂S₃, is a compound of sulfur and gallium, that is a semiconductor that has applications in electronics and photonics.

Structure[edit]

There are four polymorphs, α (hexagonal), α' (monoclinic), β(hexagonal) and γ(cubic). The alpha form is yellow. The crystal structures are related to those of ZnS with gallium in tetrahedral positions.^[3][2][4] The alpha and beta forms are isostructural with their aluminium analogues.^[5] The similarity in crystal form of gamma- with sphalerite (zinc blende), ZnS is believed to explain the enrichment of gallium in sphalerite ores.^[5]

Preparation and chemical properties[edit]

Ga₂S₃ can prepared by reacting the elements at high temperature or as a white solid by heating Ga in a stream of H₂S at high temperature (950 °C).^[2]

It may also prepared by a solid state reaction of GaCl₃ and Na₂S.^[5]

The method of production can determine the polymorphic form produced, the reaction of Ga(OH)₃ with H₂S at different temperatures is reported to produce a different polymorph depending on the temperature, α- 1020 K, β- 820 K and γ- above 873 K ^[6]

Ga₂S₃ decomposes at high temperature forming the non-stoichiometric sulfide, Ga₄S_x (4.8 < x < 5.2).^[5]Ga₂S₃ dissolves in aqueous acids and decomposes slowly in moist air forming H₂S.^[2]

Ga₂S₃ dissolves in aqueous solutions of potassium sulfide, K₂S to form K₈Ga₄S₁₀ containing the (Ga₄S₁₀)⁸⁻ anion which has an adamantane, molecular P₄O₁₀ structure.^[5]

Ternary sulfides M^IGaS₂, M^IIGa₂S₄ and M^IIIGaS₃ respectively have been of interest due to their unusual electrical properties and some of these can be prepared by reactions of Ga₂S₃ with metal sulfides e.g. CdGa₂S₄:-^[5]

Ga₂S₃ + CdS → CdGa₂S₄

Although by itself Ga₂S₃ is not a glass former it can be reacted with rare earth sulfides to form glasses e.g. the reaction with lanthanum sulfide, La₂S₃, forms gallium lanthanum sulfide glass which has interesting optical properties and is a semiconductor.^[7]

References[edit]