Vibrational spectra of augelites Al2(OH)3(XO4) (X = P, As, V)

The solid-state vibrational spectra (IR, Raman, inelastic neutron scattering (INS)) of synthetic augelites Al2(OH)3(XO4) (X = P, As. V) (space group C2/m, Z = 4) are discussed on the basis of a unit-cell group analysis. The spectral effects of deuteration, especially on the deformation modes involving the two structurally different OH-groups, and of substitution in the anionic constituents in the framework are dealt with.