Comparaison des champs de force des niobates, tantalates et antimoniates de structure columbite et trirutile

A comparison is made between the force fields calculated for the M^IINb ^V₂O ₆ and M^IITa ^V₂O ₆ columbite series and the M^IITa ^V₂O ₆ and M^IISb ^V₂O ₆ trirutile series. The trirutile structure is shown to be particularly more rigid than the columbite structure. For this reason, the trirutile structure exists only for divalent cations of small size. The stability of the two structures and their relative modifications are then compared. From a comparison of the vibrational spectra of the rutile FeSbO ₄ with those of the trirutile MSb ₂O ₆ compounds, a short-range order in the rutile structure is proposed.