Cadmoindite | |
Category: | Sulfide mineral Thiospinel group Spinel structural group |
Formula: | CdIn2S4 |
Imasymbol: | Cad[1] |
Molweight: | 470.32 g/mol |
Strunz: | 2.DA.05 |
System: | Cubic |
Class: | Hexoctahedral (mm) H-M symbol (4/m 2/m) |
Symmetry: | Fdm |
Unit Cell: | a = 10.81 Å; Z = 8 |
Color: | Black to dark brown |
Habit: | Microscopic octahedral crystals |
Fracture: | Conchoidal |
Luster: | Adamantine |
Opticalprop: | Isotropic |
Diaphaneity: | translucent |
References: | [2] [3] |
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]
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.