Structures of lanthanum and yttrium aluminosilicate glasses determined by X-ray and neutron diffraction

We have measured the structures of lanthanum and yttrium aluminosilicate glasses by X-ray and neutron diffraction and determined the interatomic distances and nearest-neighbor coordination numbers. The results obtained with the two techniques are in good agreement with each other and with recent NMR studies. The Si–O and Al–O coordination numbers are found to be 4 and 4.5, respectively. All the glasses show pronounced intermediate-range order that exhibits a reduced length scale with increasing La or Y content.