Gallium(II) sulfide, GaS, is a chemical compound of gallium and sulfur. The normal form of gallium(II) sulfide as made from the elements has a hexagonal layer structure containing Ga24+ units which have a Ga-Ga distance of 248pm.[1] This layer structure is similar to GaTe, GaSe and InSe.[1] An unusual metastable form, with a distorted wurtzite structure has been reported as being produced using MOCVD. The metal organic precursors were di-tert-butyl gallium dithiocarbamates, for example GatBu2(S2CNMe2) and this was deposited onto GaAs. The structure of the GaS produced in this way is presumably Ga2+ S2−.[2]
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| Names | |
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| Other names Gallium sulfide[citation needed] | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.031.522 |
PubChem CID | |
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| Properties | |
| GaS• | |
| Molar mass | 101.788 g mol−1 |
| Appearance | Yellow crystals |
| Density | 3.86 g cm−3 |
| Melting point | 965 °C (1,769 °F; 1,238 K) |
| −-23.0·10−6 cm3/mol | |
| Structure | |
| hexagonal, hP8 | |
| P63/mmc, No. 194 | |
| Related compounds | |
Related compounds | Gallium(III) sulfide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Single layers of gallium sulfide are dynamically stable two-dimensional semiconductors, in which the valence band has an inverted Mexican-hat shape, leading to a Lifshitz transition as the hole-doping is increased.[3]
Gallium(II) sulfide demonstrates nonlinear optical activities, including second-harmonic generation and two-photon excited fluorescence.[4]