Atomic ordering in xGa2O3•(100-x)TeO2 glasses (x=10, 17.5, 25) by X-ray diffraction

Atomic distribution functions for sGa(2)O(3).(100 - x)TeO2 glasses (x = 10, 17.5, 25) have been obtained from diffraction experiments employing a synchrotron radiation source. First neighbour atomic distances and coordination numbers in the glasses investigated have been determined by decomposing the experimental atomic distribution functions into a set of Gaussians each pertaining to a particular type of atomic pairs. It has been found that xGa(2)O(3).(100 - x)TeO2 glasses (x=10, 17.5, 25) may well be described as an assembly of tetrahedral GaO4 units uniformly embedded into a matrix of more (TeO3+1) or less distorted (TeO4) trigonal bipyramids where each Te in a perfect TeO4 bipyramid is surrounded by four oxygens distributed over equatorial and axial positions and each Te in a distorted TeO3+1 bipyramid has one of its axial Te-O bonds considerably elongated. (C) 1999 Published by Elsevier Science B.V. All rights reserved.