Hydrogen bond effects on compressional behavior of isotypic minerals: high-pressure polymorphism of cristobalite-like Be(OH)<sub>2</sub>
- Author(s)
- Hannah Shelton, Madison C. Barkley, Robert T. Downs, Ronald Miletich-Pawliczek, Przemyslaw Dera
- Abstract
Three isotypic crystals, SiO2 (a-cristobalite), e-Zn(OH)2 (wülfingite), and Be(OH)2 (ß-behoite), with topologically identical frameworks of corner-connected tetrahedra, undergo displacive compression-driven phase transitions at similar pressures (1.5-2.0 GPa), but each transition is characterized by a different mechanism resulting in different structural modifications. In this study, we report the crystal structure of the high-pressure ?-phase of beryllium hydroxide and compare it with the high-pressure structures of the other two minerals. In Be(OH)2, the transition from the ambient ß-behoite phase with the orthorhombic space group P212121 and ambient unit cell parameters a = 4.5403(4) Å, b = 4.6253(5) Å, c = 7.0599(7) Å, to the high-pressure orthorhombic ?-polymorph with space group Fdd2 and unit cell parameters (at 5.3(1) GPa) a = 5.738(2) Å, b = 6.260(3) Å, c = 7.200(4) Å takes place between 1.7 and 3.6 GPa. This transition is essentially second order, is accompanied by a negligible volume discontinuity, and exhibits both displacive and reversible character. The mechanism of the phase transition results in a change to the hydrogen bond connectivities and rotation of the BeO4 tetrahedra.
- Organisation(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- University of Hawaii at Manoa, University of Arizona, Arizona Historical Society
- Journal
- Physics and Chemistry of Minerals
- Volume
- 43
- Pages
- 571-586
- No. of pages
- 16
- ISSN
- 0342-1791
- DOI
- https://doi.org/10.1007/s00269-016-0818-5
- Publication date
- 05-2016
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105116 Mineralogy, 105113 Crystallography
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology, General Materials Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/8944af8c-d529-471e-b668-e1145d32d8ab