Cadmoindite
Cadmium indium sulfide mineral
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Cadmoindite (CdIn2S4) is a rare cadmium indium sulfide mineral discovered in Siberia around the vent of a high-temperature (450–600 °C) fumarole at the Kudriavy volcano, Iturup Island in the Kuril Islands. It has also been reported from the Kateřina Coal Mine in Bohemia, Czech Republic.[3]
Thiospinel group
Spinel structural group
| Cadmoindite | |
|---|---|
Cadmoindite, from Kudriavy Volcano, Far Eastern Region, Russian Federation | |
| General | |
| Category | Sulfide mineral Thiospinel group Spinel structural group |
| Formula | CdIn2S4 |
| IMA symbol | Cad[1] |
| Strunz classification | 2.DA.05 |
| Crystal system | Cubic |
| Crystal class | Hexoctahedral (m3m) H-M symbol (4/m 3 2/m) |
| Space group | Fd3m |
| Unit cell | a = 10.81 Å; Z = 8 |
| Identification | |
| Formula mass | 470.32 g/mol |
| Color | Black to dark brown |
| Crystal habit | Microscopic octahedral crystals |
| Fracture | Conchoidal |
| Luster | Adamantine |
| Diaphaneity | translucent |
| Optical properties | Isotropic |
| References | [2][3] |
Crystal structure
CdIn2S4 exhibits the spinel structure, which can be described by a cubic unit cell with 8 tetrahedrally coordinated and 16 tetrahedrally coordinated cation sites. The distribution of Cd(II) and In(III) over the cation sites is difficult to elucidate from standard X-ray diffraction techniques because the two species are isoelectronic, but both Raman spectroscopy measurements on synthetic samples[4] and density functional theory simulations[5] indicate that about 20% of the tetrahedral sites are occupied by In(III) cations.
