Exploring the coordination change of vanadium and structure transformation of metavanadate MgV2O6 under high pressure

Raman spectroscopy, synchrotron angle-dispersive X-ray diffraction (ADXRD), first-principles calculations, and electrical resistivity measurements were carried out under high pressure to investigate the structural stability and electrical transport properties of metavanadate MgV 2 O 6 . The results have revealed the coordination change of vanadium ions (from 5+1 to 6) at around 4 GPa. In addition, a pressure-induced structure transformation from the C2 / m phase to the C2 phase in MgV 2 O 6 was detected above 20 GPa, and both phases coexisted up to the highest pressure. This structural phase transition was induced by the enhanced distortions of MgO 6 octahedra and VO 6 octahedra under high pressure. Furthermore, the electrical resistivity decreased with pressure but exhibited different slope for these two phases, indicating that the pressure-induced structural phase transitions of MgV 2 O 6 was also accompanied by the obvious changes in its electrical transport behavior.