Solid-state and sol-gel synthesis of neodymium molybdate Nd5Mo3O16+δ and study of their crystal structure in the temperature range of 300-700 K by the neutron diffraction

The solid-state and sol-gel synthesis of Nd5Mo3O16+delta neodymium molybdate has been investigated. The sequence of chemical transformations was studied using differential thermal analysis, X-ray diffraction analysis, and infrared spectroscopy. It has been demonstrated that the solid-state synthesis occurs stepwise through the formation of Nd2(MoO4)3 and phases with monoclinic structures. The using of the sol-gel method allows obtaining a single-phase neodymium molybdate directly after decomposition of the organic precursor and decreasing of the synthesis temperature by 200 K. The investigation of the crystal structure was carried out by high resolution neutron diffraction, which revealed non-uniform changes in the neodymium-oxygen interatomic distances with increasing temperature.