Phase relations in Na2MoO <sub>4</sub>-Ln <sub>2</sub>(MoO <sub>4</sub>) <sub>3</sub>-Zr(MoO4)2 (Ln = Nd, Sm, Er, Lu) systems
X-ray diffraction study of the solid-state interaction in the Na <sub>2</sub>MoO <sub>4</sub>-Ln <sub>2</sub>(MoO <sub>4</sub>) <sub>3</sub>-Zr(MoO <sub>4</sub>) <sub>2</sub> (Ln = Nd, Sm, Er, Lu) systems was performed. Quasi-binary sections were identified and subsolidus phase diagrams of the studied systems were revealed.