Ge-O Distance Research Articles

Na<SUB>2</SUB>O-GeO<SUB>2</SUB>ガラスの構造

In order to clarify the structural change in GeO2 glass due to the addition of alkali metal oxides, the radial distribution functions for Na2O-GeO2 glasses containing 0, 10, 20 mol%Na2O were determined by X-ray diffraction measurement.The results are summarized as follows:(1) The structure of GeO2 glass was composed of tetrahedral GeO4 basic structural units with an average Ge-O distance of 1.74×10−10 m. The average structure of GeO2 glass in the short range resembled that of the quartz modification.(2) Analysis of the radial distribution functions indicated that oxygen coordinations around some of Ge4+ ions in Na2O-GeO2 glasses changed from GeO4 tetrahedra to GeO6 octahedra when Na2O was added up to 20 mol%.

New Method to Measure Structural Disorder: Application to GeO2Glass

A new method is presented for measuring thermal or structural disorder. The additional disorder in the first Ge-O and Ge-Ge distances in amorphous Ge${\mathrm{O}}_{2}$ was measured by comparison with crystalline ($\ensuremath{\alpha}$-quartz) Ge${\mathrm{O}}_{2}$, and showed no additional disorder in the Ge-O distances but deviations in the Ge-Ge distance consistent with a \ifmmode\pm\else\textpm\fi{}6.5\ifmmode^\circ\else\textdegree\fi{} variation about a Ge-O-Ge bond angle of 130\ifmmode^\circ\else\textdegree\fi{}. These results rule out the proposed microcrystalline models.