Structures, Phase Stability, Amorphization, and Decomposition of V6O13 at High Pressures and Temperatures: Synthesis of Rutile-Related V0.92O2

• Published in: Crystal growth & design Vol. 24; no. 13; pp. 5582 - 5592
• Main Authors: Grzechnik, Andrzej, Hakala, B. Viliam, Kurig, Sophia, Walte, Nicolas, Tsujino, Noriyoshi, Kakizawa, Sho, Higo, Yuji, Zagorac, Dejan, Zagorac, Jelena, Dronskowski, Richard, Schön, J. Christian, Friese, Karen
• Format: Journal Article
• Language: English
• Published: American Chemical Society 03-07-2024
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.4c00363

The stability of mixed-valence V6O13 at high pressures and high temperatures is studied experimentally in multianvil presses both ex situ and in situ using synchrotron energy-dispersive powder diffraction. V6O13 starts to amorphize and decomposes above 18.5 GPa at room temperature. It transforms to rutile-related V0.92O2 above 500 K in the pressure range up to about 15–17.5 GPa. The crystal structure of this new phase (C12/m1, Z = 4) was determined from laboratory single-crystal and powder X-ray diffraction data measured on single crystals grown at 10 GPa and 1373 K. The characteristic feature is the presence of two zigzag V–V chains. One of them has equidistant V atoms, while the other is with short and long V–V distances. In the average-ordered structure (P2/m, Z = 2), both V–V chains are linear and equidistant. The M2 polymorph of VO2 is considered to be the ordered (though distorted) variant of V0.92O2. The experiments are complemented by density functional theory calculations and global explorations of the energy landscape of V6O13 and V0.92O2 compounds at high pressures using a multimethodological approach to construct and predict feasible structures.