Study of niobium germanate glasses by the light combination scattering spectroscopy method

Glasses of system K2O - Nb2O5 - GeO2 were studied by three cross sections. It is shown that from low concentrations of Nb2O5 in the range of alkaline oxide concentration K2O>0.3 mol. parts niobium ion enters the net of niobium-germanate glasses in tetrahedral coordination state. The increase in Nb2O5 content results in the appearance of a considerable number of octahedrically coordinated Nb5+ ions. Over the whole range of concentrations niobium is a reticulator and (NbO4)3- substitutes for (GeO4)4- in isomorphous way and constructs a unified mixed net with arbitrary distributed niobate and germanate tetrahedrons