High-pressure phases of V2O5: an application of an in situ X-ray observation method to high-pressure synthesis of materials

The high-pressure and high-temperature behavior of V2O5 With a layered-orth orhombic structure was studied by both in-situ X-ray diffraction observatio ns and recovery experiments. Two quenchable high-pressure phases (HPP1 and HPP2) were observed in the pressure and temperature range up to 11 GPa and 700 degreesC. The phase transition to the HPP1 was observed by elevating th e temperature above 300 degreesC in the pressure range up to 7 GPa. The HPP 1 was found to have an orthorhombic cell (a = 7.100(7)Angstrom, b = 6.294(5 )Angstrom and c = 3.578(2)Angstrom at 0.1 MPa and 27 degreesC. The phase tr ansition to the HPP2 was also observed in an elevating temperature process above 9 GPa. Unit cell parameters of the HPP2 have not yet been determined. (C) 2001 Elsevier Science B.V. All rights reserved.