ANOMALOUS X-RAY-SCATTERING STUDY OF LOCAL STRUCTURES IN THE SUPERIONIC CONDUCTING CLASS (CUI)(0.3)(CU2O)(0.35)(MOO3)(0.35)

The anomalous X-ray scattering (AXS) method using Cu and Mo K absorpti on edges has been employed for obtaining the local structural informat ion of superionic conducting glass having the composition (CuI)(0.3)(C u2O)(0.35)(MoO3)(0.35). The possible atomic arrangements in near-neigh bor region of this glass were estimated by coupling the results with t he least-squares analysis so as to reproduce two differential intensit y profiles for Cu and Mo as well as the ordinary scattering profile. T he coordination number of oxygen around Mo is found to be 6.1 at the d istance of 0.187 nm. This implies that the MoO6 octahedral unit is a m ore probable structural entity in the glass rather than MoO4 tetrahedr a which has been proposed based on infrared spectroscopy. The pre-peak shoulder observed at about 10 nm(-1) may be attributed to density flu ctuation originating from the MoO6 octahedral units connected with the corner sharing linkage, in which the correlation length is about 0.8 nm. The value of the coordination number of I- around Cu+ is estimated as 4.3 at 0.261 nm, suggesting an arrangement similar to that in molt en CuI.