Chemistry:Niobium(IV) fluoride

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Niobium(IV) fluoride
Niobtetrafluorid.png
Unit cell of niobium(IV) fluoride.
Names
IUPAC name
Niobium(IV) fluoride
Other names
  • Niobium tetrafluoride
Identifiers
3D model (JSmol)
ChemSpider
Properties
NbF
4
Molar mass 168.9 g/mol
Appearance black solid
Melting point 350 °C (662 °F; 623 K) (decomposes)
Structure[1]
tetragonal
I4/mmm
a = 4,0876(5) Å, c = 8,1351(19) Å
[6]Nb
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Niobium(IV) fluoride is a chemical compound with the formula NbF
4
. It is a nonvolatile black solid.

Properties

NbF
4
absorbs vapor strongly and turns into NbO
2
F
in moist air. It 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:[2]

2 NbF
4
→ NbF
5
+ NbF
3
(at 350 °C)

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. 1.0 1.1 Bandemehr, Jascha; Conrad, Matthias; Kraus, Florian (29 July 2016). "Redetermination of the crystal structure of NbF4". Acta Crystallographica Section E 72 (8): 1211–1213. doi:10.1107/S2056989016012081. PMID 27536416. 
  2. 张青莲 (1981). 无机化学丛书. Beijing: Science Press. pp. 323. ISBN 7-03-002238-6.