Refined crystal structure of parakeldyshite and the genetic crystal chemistry of zirconium minerals with [Si2O7] diorthogroups
- Author(s)
- Ekkehart Tillmanns, Uwe Kolitsch
- Abstract
The structure of the mineral parakeldyshite Na1.93ZrSi2O6.93(OH)0.07is refined by X-ray diffraction analysis. The main crystallographic data are as follows: space group , a= 6.617(2) Å, b= 8.813(1) Å, c=5.426(1) Å, alpha = 87.26(3)°, beta = 85.68(3)°, gamma = 71.45(3)°, and RF= 0.0153. The initial structural model of this mineral is confirmed. Within this model, the structure of parakeldyshite is based on the heteropolyhedral framework formed by [Si2O7] diorthogroups, which are linked together through isolated zirconium octahedra. The fundamental difference between the structure under investigation and the initial structural model is associated with the arrangement of the extra framework cations. A comparative crystal chemical analysis of the zirconium silicates with [Si2O7] diorthogroups is performed.
- Organisation(s)
- Department of Mineralogy and Crystallography
- Journal
- Crystallography Reports
- Volume
- 52
- Pages
- 1066-1071
- No. of pages
- 6
- ISSN
- 1063-7745
- Publication date
- 2007
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105113 Crystallography
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/ad51fb98-15bb-4968-a192-6a0ca6bf9c47