Abstract
Theoretical and experimental methods have been conducted to study the high-pressure structures of CaWO4, which have never been definitely determined during the past decades. By using the CALYPSO method, in addition to the previously known tetragonal scheelite structure (I41/a), monoclinic fergusonite structure (I2/a), and the orthorhombic structure (Cmca) predicted by previous works, we have found two other new phases of CaWO4 at higher pressure: monoclinic P21/c and P21/m structures. Although the P21/c structure has the lowest energy (above 26.0 GPa), synchrotron-radiation-based X-ray diffraction measurements show that only the P21/m structure stably exists above 38.0 GPa. The kinetical hindrance of P21/c structure formation in the experiment has been attributed to its larger W-O coordination number than that of the P21/m structure at high pressure.
Original language | English |
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Pages (from-to) | 1947-1951 |
Number of pages | 5 |
Journal | Physica Status Solidi (B) Basic Research |
Volume | 253 |
Issue number | 10 |
DOIs | |
State | Published - Oct 1 2016 |
Keywords
- CALYPSO
- CaWO
- X-ray diffraction
- crystal structure
- high pressure
- phase transition