Antimonselite
Antimony triselenide is the chemical compound with the formula Sb2Se3. The material exists as the sulfosalt mineral antimonselite (IMA symbol: Atm), which crystallizes in an orthorhombic space group. In this compound, antimony has a formal oxidation state +3 and selenium −2. The bonding in this compound has covalent character as evidenced by the black color and semiconducting properties of this and related materials. The low-frequency dielectric constant (ε0) has been measured to be 133 along the c axis of the crystal at room temperature, which is unusually large.
Intro adapted from Wikipedia (CC BY-SA).
Antimonselite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Sb₂Se₃.
It crystallizes in the orthorhombic crystal system (space group Pbnm). It is a member of the Stibnite structural group.
Key properties: Mohs hardness 3.3; specific gravity 5.969; Black streak; Metallic luster; optically biaxial.
IMA symbol Atm, IMA status: approved, named in 1992.
Found in uraniferous calcite veins in a hydrothermal U–Hg–Mo polymetallic deposit (near Kaiyan, China).
It is found associated with Pyrite, sphalerite, galena, ferroselite, clausthalite, uraninite, cinnabar, hematite, calcite (near Kaiyan, China); gold, clausthalite, selenian famatinite.
The name refers to ANTIMONy and SELenium in the composition.