New triple rubidium and iron molybdate based on zirconium molybdate

A new ternary molybdate Rb5FeZr(MoO4)6 was synthesized by ceramic technology and grown by spontaneous solution-melt crystallization. The crystal structure of Rb5FeZr(MoO4)6 was described as trigonal (space group R 3¯ c), having the following unit cell parameters: a ​= ​10.6187(6); c ​= ​38.173(2) Å; V ​= ​3727.6(2) Å3; Z ​= ​6. The crystal structure of the compound consists of a mixed framework of the Zr/Fe-octahedra connected with Mo-tetrahedra and Rb-polyhedra via vertices. It was found that the conductivity of Rb5FeZr(MoO4)6 increases with increasing temperature and at 873 ​K it reaches a value of σ ​= ​0.5·10−2 ​S/сm. Furthermore, a first-order phase transition occurs at 751 ​K.