Cadmoindite
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.[2]
| Cadmoindite | |
|---|---|
 Cadmoindite, from Kudriavy Volcano, Far Eastern Region, Russian Federation | |
| General | |
| Category | Sulfide mineral Thiospinel group Spinel structural group |
| Formula (repeating unit) | CdIn2S4 |
| 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 | [1] [2] |
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[3] and density functional theory simulations[4] indicate that about 20% of the tetrahedral sites are occupied by In(III) cations.
References
- Cadmoindite Webmineral Data
- Cadmoindite mineral information from Mindat.org
- Ursaki, V. V.; Manjon, F. J.; Tiginyanu, I. M.; Tezlevan, V. E. (2002). "Raman scattering study of pressure-induced phase transitions in MIn2S4 spinels". J. Phys.: Condens. Matter. 14: 6801. doi:10.1088/0953-8984/14/27/304.
- Seminovski, Y.; Palacios, P.; Wahnon, P. M.; Grau-Crespo, R. (2012). "Band gap control via tuning of inversion degree in CdIn2S4 spinel". Applied Physics Letters. 100: 102112. arXiv:1202.4752. Bibcode:2012ApPhL.100j2112S. doi:10.1063/1.3692780.