The role of modifier’s cation valence in structural properties of TeO2-based glasses

The compositional invariance of the Raman spectra of (1 − x)TeO2–xMnOm glasses (M = Ti, Nb) is analyzed and interpreted as evidence for the conservatism of a framework-type constitution inherent to such glasses. This is assigned to the chemical similarity of cations in the X–O–Y bridges (X, Y = Te4+, Ti4+, Nb5+) considered as the framework building blocks. It is concluded that the atoms of metals having valence IV and V can be placed into the category of such cations, to which certain of the atoms with valence III can be added.