An X-ray diffraction study of the structure of barium fluorozirconate and fluorohafnate glasses

Two binary glasses have been prepared in the ZrF₄BaF₂ and HfF₄BaF₂ systems, containing 64 mol.% ZrF₄ and 66 mol.% HfF₄, respectively. The two plate-like glass samples were studied by X-ray diffraction, and the resulting data were subjected to a Fourier analysis. The pair correlation functions thus obtained yield a ZrF (or HfF) nearest neighbor coordination number of ～ 7.6 for both glasses. The second peak in the correlation functions has been assigned to a combination of FF and BaF interactions, while the third peak is probably due in part to ZrZr (Hf-Hf) interactions. The diffraction data have been compared with the predictions of structural models for barium fluorozirconate and fluorohafnate glasses.