Reexamination of KNO3IV and transition rate of KNO3II ⇋ KNO3IV*
- 1 December 1962
- journal article
- research article
- Published by Walter de Gruyter GmbH in Zeitschrift für Kristallographie
- Vol. 117 (5-6) , 399-410
- https://doi.org/10.1524/zkri.1962.117.5-6.399
Abstract
Use of a modified Bridgman anvil device and a supported beryllium cylinder with both molybdenum and copper radiation has yielded sufficiently accurate diffraction data to warrant a general attempt at indexing of the high-pressure polymorph KNO3 IV. Indexing is best accomplished on the basis of an orthorhombic cell having a = 11.048 Å, b = 8.367 Å, c = 7.402 Å, and 10 KNO3 per cell. The larger RbNO3-type unit cell established by Jamieson (1956) with Z = 18 is open to question because of new diffraction data which do not allow centering on C. Although a complete structure analysis has not yet been carried out, possible positions for the K+ ions are suggested having the symmetry of the space group Pmn21. Rate studies on the transition KNO3 II ⇋ KNO3 IV show an over-all approach to first-order kinetics but in detail reveal several growth stages.Keywords
This publication has 4 references indexed in Scilit:
- SomeX-Ray Diffraction Data onKNO3IV, a High Pressure PhaseZeitschrift für Kristallographie, 1956
- A Diamond Bomb for Obtaining Powder Pictures at High PressuresReview of Scientific Instruments, 1950
- Effects of High Shearing Stress Combined with High Hydrostatic PressurePhysical Review B, 1935
- Polymorphic Changes under Pressure of the Univalent NitratesProceedings of the American Academy of Arts and Sciences, 1916