Crystalline phase effects on esca valence bands of Zr(IV) and Ti(IV) acid phosphates

Abstract

The valence bands (V.B.) of ESCA spectra of Zr(IV) and Ti(IV) acid phosphates in different crystalline phases are reported. The various bands are assigned by comparison with Li 3PO 4. Variations on changing the crystalline phase for compounds having the same M(IV) ion are found. Two types of molecular orbitals are mainly involved. One related to PO bonds is affected by the crystalline phase. The other, related to M(IV)O bonds and confined into the layers of the compounds, are less sensitive to crystalline environment. Variation in the symmetry of the tetrahedral type PO 3− 4 anion are proposed to be mainly responsible of the observed effects.