A Structural Study on AgI–Ag₂O–CrO₃ Glass

抄録

A structural investigation for a 50AgI–20Ag₂O–30CrO₃ (in mole %) glass has been carried out by using X-ray diffraction (XRD) and the extended X-ray absorption fine structure (EXAFS) techniques. The analysis of the EXAFS spectrum of the glass at the Ag K-edge reveals that the distance between a silver (I) and an iodide ions, r_Ag–I, and the average number of iodide ions around an Ag⁺, n_Ag–I, are 2.874(4) Å and 1.6(1), respectively. Two Ag–O distances separated by only 0.38 Å (Δr_Ag–I) are deconvoluted from the total Ag–O peak in the spectrum. The results by the X-ray diffraction measurement coincide with those by the EXAFS study within experimental uncertainties: r_Ag–I=2.860(1) Å, n_Ag–I=1.34(1), and Δr_Ag–I=0.35 Å. The intramolecular structural parameters of CrO₃ are determined to be r_Cr–O=1.718 Å, and n_Cr–O=5.58. Short range ordering of atoms is discussed on the basis of the radial distribution function (RDF).