Structural investigation of the Na-Fe-Mo-O system.

Four new crystalline structures within the Na-Fe-Mo-O system are reported: sodium tetrairon pentamolydate (1), NaFe(4)(MoO(4))(5), alpha-sodium diiron trimolybdate (2), alpha-NaFe(2)(MoO(4))(3), beta-sodium diiron trimolybdate (3), beta-NaFe(2)(MoO(4))(3), trisodium diiron trimolybdate (4), Na(3)Fe(2)(MoO(4))(3). All these structures belong to orthomolybdate class of compound and are described as networks of [FeO(6)] octahedra and [MoO(4)] tetrahedra. They are compared with each other and with other related structures.