Molybdates are of a great interest due to their ionic conductivity, negative thermal expansion, and immobilization of radionuclides. The new mineral tancaite-(Ce), FeCe(MoO4)3•3H2O, shows a new structure type never observed in natural and synthetic molybdates. Its cubic average structure may be described as a derivative of the perovskite structure, in which Fe-centred octahedra are linked through MoO4 groups. The ordering of Mo and O atoms results in one or more complex superstructures.
Molybdates are of a great interest due to their ionic conductivity, negative thermal expansion,...