New triple molybdate K5ScHf(MoO4)6: Synthesis, properties, structure and phase equilibria in the M2MoO4-Sc2(MoO4)3-Hf(MoO4)2 (M = Li, K) systems

Subsolidus phase relations in the M2MoO4-Sc-2(MoO4)(3)-Hf(MoO4)(2) = Li, K) systems have been studied by the method of intersecting cuts. No new triple molybdates have been identified in the Li2MoO4-Sc-2(MoO4)(3)-Hf(-MoO4)(2) system and a new triple molybdate K5ScHf(MoO4)(6) is formed in the K2MoO4-Sc-2(MoO4)(3)-Hf(MoO4)(2) system. The structure of K5ScHf(MoO4)(6), have been determined in space group R (3) over barc through Rietveld analysis of X-ray powder diffraction data. The melting point of molybdate is 999 K. The compound has high ion conductivity (about 10(-3) S cm(-1)).