Synthesis and redetermination of the crystal structure of NbF₅

Abstract

Single crystals of NbF5, niobium(V) fluoride, have been obtained by the reaction of niobium metal in a stream of dilute elemental fluorine at 473 K and subsequent sublimation. The as-obtained bulk phase compound was shown to be pure by powder X-ray diffraction at 293 K and by IR and Raman spectroscopy. A single-crystal X-ray analysis was conducted at 100 K. In comparison to the previously reported structure model [Edwards (1964). J. Chem. Soc. pp. 3714–3718], the lattice parameters and fractional atom coordinates were determined to much higher precision and individual, anisotropic displacement parameters were refined for all atoms.

Synthesis, Characterization, and Polymorphism of [H3O][NbF6]: A Polar and Possibly Ferroelectric Oxonium Salt

“…All solid starting materials were stored and handled in an Ar-filled (Ar 5.0, Nippon Gases) glove box (MBraun). NbF 5 was prepared according to the literature [16,48,49] by heating Nb metal sheets (TANIOBIS) in a stream of diluted fluorine F 2 (F 2 /Ar 20 : 80, V/V, Solvay) at 150 °C. The product was sublimed into a PFA U-trap and used without further purification.…”

“…However, a crystal structure of CsCl type could not be ruled out. [15] During our efforts to find novel accesses to high purity NbF 5 , [16] we obtained the compound [H 3 O][NbF 6 ] as a decomposition product of NbF 5 when exposed to moist air. We also observed its formation as a byproduct in the reaction of Nb 2 O 5 with liquid anhydrous HF (aHF).…”