AbstractRaman measurements on the Gd2(ZrxTi1−x)2O7, solid solution show increasing peak widths as the composition is varied from Gd2Ti2O7, to Gd2Zr2,O7. The increase in peak width is interpreted as reflecting an increase in structural disorder with increasing x in this pyrochlore structure material. Structural disorder occurs readily in such oxides by the formation of cation anti-site defects and anion frenkel defects. We have previously observed that this leads to a marked increase in oxygen ion conduction with increasing x. Preliminary results also indicate that certain peaks in the Raman spectra are characteristic of the end members of the solid solution and may occur at the same frequency independent of composition. The Raman results are discussed in relation to earlier x-ray diffraction and ionic conductivity data obtained in this group.