Crystal structure and hydrogen occupation in H x V2O5(x=0.0?3.9)

• DOI: 10.1007/bf00975082
• Publication Date: 2005-01-13T09:57:13Z
• Authors: A. Yoshikawa; K. Yagisawa; M. Shimoda
• Keywords: Orthorhombic crystal system; Lattice constant; Crystal (programming language)

Changes in the crystal structure and the lattice constants of powdered crystalline V2O5 after absorption of hydrogen were measured, as a function of the concentration, by X-ray diffractometry. The diffraction spectra obtained showed that three kinds of phases, α (x<0.4 in H x V2O5), Β (co-existing with either terminal phase in the range of 0.4⩽x<3.2) and γ (3.2⩽x⩽3.9), appear up tox=3.9, which was found to be the upper limit of the absorption at 70‡C under a hydrogen pressure of 5 MPa. The crystal system of the three phases was determined to be orthorhombic, although the lattice constants differed. The diffraction lines were broadened, and the background of the X-ray spectra grew with hydrogenation, especially in the γ-region, which indicates the growth of the lattice distortion and a quasi-amorphous state. The occupation of hydrogen atoms in each phase is discussed on the basis of the experimental results.