 | |
 | |
| Names | |
|---|---|
| IUPAC name Germanium selenide | |
| Other names germanium(II) selenide | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.031.862 |
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| |
| Properties | |
| GeSe | |
| Molar mass | 151.57 g/mol |
| Appearance | black |
| Density | 5.56 g/cm3 |
| Melting point | 667 °C (1,233 °F; 940 K) (decomposes) |
| Band gap | 1.33 eV (direct)[1] |
Refractive index (nD) | 2.5 |
| Structure | |
| Orthorhombic | |
| Pnma | |
| Related compounds[2] | |
Otheranions | Germanium monoxide Germanium monosulfide Germanium telluride |
Othercations | Tin selenide Lead selenide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Germanium monoselenide is achemical compound with theformula GeSe. It exists as black crystalline powder havingorthorhombic (distortedNaCl-type) crystal symmetry; at temperatures ~650 °C, it transforms into the cubic NaCl structure.[3] GeSe has been shown to have stereochemically active Ge 4s lone pairs that are responsible for the distorted structure and the relatively high position of the valence band maximum with respect to the vacuum level.[4]
To grow GeSe crystals, GeSe powder is vaporized at the hot end of a sealed ampule and allowed to condense at the cold end. Usual crystals are small and show signs of irregular growth, caused mainly by convective motion in the gaseous medium. However, GeSe grown under condition of zero-gravity and reduced convection aboard theSkylab are ~10 times larger than Earth-grown crystals, and are free from visual defects.[5][6]
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