155Gd Mössbauer spectroscopic and X-ray diffraction study of the Zr1−xGdxO2−x/2 (0

155Gd Mössbauer spectroscopy has been applied for the GdxZr1−xO2−x/2 system, to elucidate the local structure around the Gd3+ over the entire 00.50. Their basic features were unchanged upon disordering above 1550 °C. These Mössbauer results suggest that the GdxZr1−xO2−x/2 solid solution (0.18≤x≤0.62) has essentially a pyrochlore(P)-type local structure, whether long-range ordered or not, both the Gd–O bond strength and anisotropy attaining a maximum at x=0.50.