Phase formation in Na2MoO4-Cs2MoO4-Ln2(MoO4)3 systems and crystal structure of new triple molybdate Cs7Na5Yb2(MoO4)9

Phase formation in subsolidus areas of Na2MoO4-Cs2MoO4-Ln2(MoO4)3 (Ln = La, Nd, Dy, Yb) systems was studied by «intersecting cuts» method. It has been established that systems Na2MoO4-Cs2MoO4-Ln2(MoO4)3 (Ln = La, Nd, Dy) are not phase-forming, but Na2MoO4-Cs2MoO4-Yb2(MoO4)3 is characterized by formation of triple molybdates. Formation of intermediate phases analogous to ytterbium ones was also found in thulium and lutetium systems. Triple molybdate Cs7Na5Yb2(MoO4)9 crystals were obtained and crystal structure of this compound was determined by X-ray structurе analysis. Cs7Na5Yb2(MoO4)9 crystallizes in trigonal system (sp. gr. R32, Z=3, a=10.5107(15), c=36.358(7) Å, R=0.0348) and has a framework structure. Structure features of this phase suggest the exhibiting of cation-conducting and nonlinear optical properties.