La6Br10Fe: A La6Fe Octahedron with a Mixed M6X12/M6X8 Type Environment

The title compound was synthesized from La, LaBr3, and Fe under Ar atmosphere at 800 °C. It crystallizes in space group P41 (No. 76) with lattice constants a = 8.255(1) Å and c = 30.033(6) Å. The structure features an isolated Fe-centered La6 octahedron with all corners, 9 of its 12 edges, and 3 of its 8 triangular faces coordinated, bridged, or capped by Br atoms. The La6Fe octahedron is significantly distorted, and the La coordination by Br atoms deviates from the common close-packing arrangements found in other reduced rare earth metal halides. Band structure, bonding, and physical properties of the compound have been investigated.