# Niobium(IV) fluoride

Names Identifiers Unit cell of niobium(IV) fluoride. IUPAC name Niobium(IV) fluoride Other names Niobium tetrafluoride CAS Number 13842-88-1 3D model (JSmol) Interactive image ChemSpider 9253762 PubChem CID 11078613 InChI InChI=1S/4FH.Nb/h4*1H;/q;;;;+4/p-4Key: TUDPVASEPFIHNB-UHFFFAOYSA-J SMILES F[Nb](F)(F)F Chemical formula NbF4 Molar mass 168.9 g/mol Appearance black solid Melting point 350 °C (662 °F; 623 K) (decomposes) Crystal structure tetragonal Point group I4/mmm Lattice constant a = 4,0876(5) Å, c = 8,1351(19) Å Coordination geometry [6]Nb Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is  ?) Infobox references

Niobium(IV) fluoride is a chemical compound with the formula NbF4; it is a nonvolatile black solid. It absorbs vapor strongly. It turns into NbO2F in moist air. NbF4 reacts with water to form a brown solution and a brown precipitate whose components are unknown. It is stable between 275 °C and 325 °C when heated in a vacuum. However, it disproportionates at 350 °C rapidly to form niobium(V) fluoride and niobium(III) fluoride:

${\displaystyle \mathrm {\ 2NbF_{4}\rightarrow NbF_{5}+NbF_{3}} }$(at 350 °C)[2]

## Structure

Niobium(IV) fluoride adopts a crystal structure analogous to that of tin(IV) fluoride, in which each niobium atom is surrounded by six fluorine atoms forming an octahedron. Of the six fluorine atoms surrounding a single niobium atom, four are bridging to adjacent octahedra, leading to a structure of octahedra connected in layers.[1]

## References

1. ^ a b Bandemehr, Jascha; Conrad, Matthias; Kraus, Florian (29 July 2016). "Redetermination of the crystal structure of NbF4". Acta Crystallographica Section E: Crystallographic Communications. 72 (8): 1211–1213. doi:10.1107/S2056989016012081. PMC 4971875. PMID 27536416.
2. ^ 张青莲 (1981). 无机化学丛书. Beijing: Science Press. p. 323. ISBN 7-03-002238-6.