Compositional and Structural Versatility in an Unusual Family of anti-Perovskite Fluorides: [Cu(H2O)4]3[(MF6)(M′F6)]

A series of six anti-perovskite fluorides of the type [Cu­(H2O)4]3(M1–xM′xF6)2 (where M and M′ = V, Cr, Mn, Fe as well as M = Fe and M′ = V and Cr) was synthesized as high-quality single crystals via a mild hydrothermal route. These materials belong to a class of perovskite-based structures in which the anions and cations of the regular ABX3 perovskite structure have exchanged positions. Two complex anions, MF63– and M′F63–, occupy the normal A and B cation positions, while three complex cations, [Cu­(H2O)4]2+, occupy the normally anionic X positions. As in the ABX3 compositions, the A and B positions can be occupied by different complex anions, allowing for the preparation of a wide range of compositions. Magnetic property measurements were performed on all six phases, and complex magnetic behavior was observed at low temperatures in the Mn, Fe, and bimetallic Fe/V and Fe/Cr phases.