The crystal chemistry of the amphiboles. I: Refinement of the Crystal structure of ferrotschermakite
- 1 March 1973
- journal article
- Published by Mineralogical Society in Mineralogical Magazine
- Vol. 39 (301) , 36-48
- https://doi.org/10.1180/minmag.1973.039.301.05
Abstract
Three-dimensional counter-diffractometer data and a full-matrix least-squares method have been used to refine the crystal structure of a ferrotschermakite in the space group C2/m. The chemical composition of the amphibole is with cell parameters a 9·8179(7), b 18·1060(14), c 5·3314(5) Å, and β 105·00(I). Cation site-occupancies were initially assigned by ionic-radius criteria and refined with the constraint that the sum total of the site-occupancies be equal to the chemical analysis.The A-site shows positional and substitutional disorder and can be better represented by two sites, one on the mirror plane and the other on the 2-fold axis.Unit weights were used throughout the refinement and the final R-factor for 1207 observed nonequivalent reflections was 4·5 %.Keywords
This publication has 3 references indexed in Scilit:
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