Identification of the high-pressure phases of α-SnWO4 combining x-ray diffraction and crystal structure prediction

• Published in: Physica. B, Condensed matter Condensed matter, 2025-01, Vol.696, p.416666, Article 416666
• Main Authors: Diaz-Anichtchenko, Daniel, Ibáñez, Jordi, Botella, Pablo, Oliva, Robert, Kuzmin, Alexei, Wang, Li, Li, Yuwei, Muñoz, Alfonso, Alabarse, Frederico, Errandonea, Daniel
• Format: Article
• Language: English
• Subjects: Crystal structure; Density-functional theory; High-pressure; Phase transition; X-ray diffraction
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2024.416666

We have characterized the high-pressure behavior of α-SnWO4. The compound has been studied up to 30 GPa using a diamond-anvil cell and synchrotron powder X-ray diffraction. We report evidence of two structural phase transitions in the pressure range covered in our study, and we propose a crystal structure for the two high-pressure phases. The first one, observed around 12.9 GPa, has been obtained combining indexation using DICVOL and density-functional theory calculations. The second high-pressure phase, observed around 17.5 GPa, has been determined by using the CALYPSO code, the prediction of which was supported by a Le Bail fit to the experimental X-ray diffraction patterns. The proposed structural sequence involves two successive collapses of the unit-cell volume and an increase in the coordination number of Sn and W atoms. The room-temperature equations of state, the principal axes of compression and their compressibility, the elastic constants, and the elastic moduli are reported for α-SnWO4 and for the two high-pressure phases.