Crystal Structure of and Electron Spin Resonance of Mn2+ in MgV2O6

Abstract

MgV2O6 crystallizes in the monoclinic space group C2/m with lattice parameters a = 9.279(7), b = 3.502(2), c = 6.731(6) Å and β = 111.77(6)° with Z = 2. The structure was refined, at room temperature, utilizing 593 symmetry independent reflections, by full matrix least squares to a final R value of 0.032. The structure consists of Mg2+ lying at a site of 2/m symmetry octahedrally coordinated to oxygen atoms with a mean separation of 2.140 Å. All the remaining atoms lie in crystallographic mirror planes with the V ion coordinated to six oxygen atoms with bond distances ranging from 1.666 to 2.671 Å. The spin Hamiltonian parameters for Mn2+ were determined at room temperature and again at liquid N2 temperatures. As these values are invariant with temperature there is no indication of a phase transformation in Mg(VO3)2 to a lower symmetry space group. The spin Hamiltonian parameters are gx = 2.0042, gy = 2.0090, gz = 2.0005; D = −459 G, E = 65 G, and A = −78 G with one of the principal axes, X, parallel to the b-axis and the Z-axis at an angle of 5° to the c-axis.