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

Abstract Subsolidus phase relations in the M2MoO4–Sc2(MoO4)3–Hf(MoO4)2 (M ​= ​Li, K) systems have been studied by the method of “intersecting cuts”. No new triple molybdates have been identified in the Li2MoO4–Sc2(MoO4)3–Hf(MoO4)2 system and a new triple molybdate K5ScHf(MoO4)6 is formed in the K2MoO4–Sc2(MoO4)3–Hf(MoO4)2 system. The structure of K5ScHf(MoO4)6, have been determined in space group R 3 ‾ c 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).