Investigations on the structural and thermal expansion properties of compounds Dy2−xLnxMo4O15 (Ln = Ho and Sm)

Crystal structures and thermal expansion properties of Dy2−xLnxMo4O15 (Ln = Ho (x = 0.0–2.0) and Sm (x = 0.0–0.4)) have been investigated by means of X-ray diffraction (XRD). Dy2−xLnxMo4O15 (Ln = Ho and Sm) crystallizes in monoclinic lattice with space group P21/c in the 25–500 °C temperature range. High-temperature XRD result reveals an anisotropic expansion in the lattice of Dy2−xLnxMo4O15 with the expansion of a- and c-axes and contraction of b-axis. Despite the shrinkage of b-axis, the volume thermal expansion coefficient of Dy2−xLnxMo4O15 is positive. The thermal expansion behavior of Dy2−xLnxMo4O15 is basically related to the temperature-induced expansion of bond Dy(Ln)–O and Mo(2)–O14.