inorganic compounds
Black single crystals of tetrasamarium(II) oxide hexaiodide, Sm4OI6, were obtained from a reaction of SmI3, SmOI, NaI, and Na in a sealed tantalum container. Sm4OI6 crystallizes in space group P63mc and, like many M4OX6 type oxide halides of divalent metals, adopts the anti-K6HgS4/Na6ZnO4 type of structure, with K6HgS4 ≃ I6OSm4. A tetrahedron of samarium(II) that incorporates an oxide ion is surrounded by 18 iodide ions which are connected further into a three-dimensional non-centrosymmetric structure. The O atom and one of the Sm atoms occupy sites with 3m symmetry, whereas the second Sm atom and both I atoms are located at sites with m symmetry.