Cadmoindite

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Cadmoindite
Cadmoindite.jpg
Cadmoindite, from Kudriavy Volcano, Far Eastern Region, Russian Federation
General
Category Sulfide mineral
Thiospinel group
Spinel structural group
Formula
(repeating unit)
CdIn2S4
Strunz classification 02.DA.05
Crystal symmetry Isometric hexoctahedral
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
Color Black to dark brown
Crystal habit Microscopic octahedral crystals
Crystal system Cubic
Fracture Conchoidal
Luster Adamantine
Diaphaneity translucent
Optical properties Isotropic
References [1] [2]

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]

Crystal Structure[edit]

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[edit]

  1. ^ Cadmoindite Webmineral Data
  2. ^ a b Cadmoindite mineral information from Mindat.org
  3. ^ 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. 
  4. ^ 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. doi:10.1063/1.3692780.