Redetermination of the crystal structure of NbF4

Single crystals of NbF4, niobium(IV) tetra­fluoride, were synthesized by disproportionation of Nb2F5 at 1273 K in a sealed niobium tube, extracted and studied by single-crystal X-ray diffraction. Previous reports on the crystal structure of NbF4 were based on X-ray powder diffraction data and the observed isotypicity to SnF4 [Gortsema & Didchenko (1965[Gortsema, F. P. & Didchenko, R. (1965). Inorg. Chem. 4, 182-186.]). Inorg. Chem. 4, 182–186; Schäfer et al. (1965[Schäfer, H., von Schnering, H. G., Niehues, K.-J. & Nieder-Vahrenholz, H. G. (1965). J. Less-Common Met. 9, 95-104.]). J. Less Common Met. 9, 95–104]. The data obtained from a single-crystal X-ray diffraction study meant the atomic coordinates could now be refined as well as their anisotropic displacement parameters, leading to a significant improvement of the structural model of NbF4. In the structure, the Nb atom is octahedron-like surrounded by six F atoms of which four are bridging to other NbF6 octa­hedra, leading to a layer structure extending parallel to the ab plane.