Occupancies of Y in garnet-type Ca_0.8Y_3.4Zr_0.8Ga_3.0O₁₂ crystal

抄録

Single crystals of a garnet-type oxide Ca_0.8Y_3.4Zr_0.8Ga_3.0O₁₂ [cubic, a = 12.6404(2) Å, Ia-3d] were synthesized by heating a compact mixture of CaCO₃, Y₂O₃, ZrO₄, and Ga₂O₃ powders at 1600 °C for 1 h in air. Crystal structure analysis by the conventional X-ray diffraction (XRD) method could not distinguish atoms of adjacent Y and Zr elements. The Y occupation at the 24c and 16a sites of Wyckoff positions in the crystal structure was revealed by δ-synthesis with anomalous X-ray scattering. The formula was determined to be (Y_0.6296(3)Ca_0.2440(2)Zr_0.1261(2))₃(Y_0.7556(5)Ca_0.0340(2)Zr_0.2109(2))₂(GaO₄)₃.