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Published on: June 13, 2015
Tyrrellite, Cu(Co0.68Ni0.32)2Se4, isostructural with spinel
Hexiong Yang1, David K Hubler, Barbara Lavina
1Department of Geosciences, University of Arizona, 1040 East 4th Street, Tucson, AZ 85721-0077, USA. hyang@u.arizona.edu
Summary
Tyrrellite, a cobalt-nickel-copper selenide mineral, has a normal spinel structure. Single-crystal X-ray diffraction refined its chemical formula to Cu(Co,Ni)2Se4.
Area of Science:
- Mineralogy
- Crystallography
- Materials Science
Background:
- Tyrrellite is a naturally occurring cobalt-nickel-copper selenide.
- Previous studies suggested a chemical formula of (Cu,Co,Ni)3Se4.
Purpose of the Study:
- To determine the precise crystal structure of tyrrellite.
- To refine the chemical formula of tyrrellite based on structural data.
Main Methods:
- Single-crystal X-ray diffraction was employed to analyze tyrrellite.
- Structural parameters, including atomic site occupancies and bond distances, were refined.
Main Results:
- Tyrrellite exhibits a normal spinel-type structure.
- Copper (Cu) occupies the tetrahedral site, while cobalt (Co) and nickel (Ni) occupy the octahedral site.
- The refined structure supports the chemical formula Cu(Co,Ni)2Se4.
Conclusions:
- The crystal structure of tyrrellite is confirmed as a normal spinel.
- The ideal chemical formula for tyrrellite is redefined as Cu(Co,Ni)2Se4 based on detailed structural analysis.
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