Uranium pentafluoride

Uranium pentafluoride

200px β form
Identifiers
CAS Number	13775-07-0 N
ChemSpider	75545 N
Jmol 3D model	Interactive image
InChI InChI=1S/5FH.U/h5*1H;/q;;;;; 5/p-5 N Key: JNVYCANIFQDNST-UHFFFAOYSA-I N InChI=1/5FH.U/h5*1H;/q;;;;;+2/p-5 Key: YKLDBRIIJYAXGS-AACRGIKGAA
SMILES [U+5].[F-].[F-].[F-].[F-].[F-]
Properties
Chemical formula	UF5
Molar mass	333.02 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Uranium pentafluoride is the inorganic compound with the chemical formula UF₅. It is a pale yellow paramagnetic solid. The compound has attracted interest because it is related to uranium hexafluoride, which is widely used to produce uranium fuel. It crystallizes in two polymorphs, called α- and β-UF₅.

Synthesis and structure

It can be produced by reduction of the hexafluoride with carbon monoxide at elevated temperatures.

2 UF₆ + CO → 2 UF₅ + COF₂

Other reducing agents have been examined.

The α form is a linear coordination polymer consisting of chains of octahedral uranium centers in which one of the five fluoride anion forms a bridge to the next uranium atom. The structure is reminiscent of that for vanadium pentafluoride.

In β form, the uranium centers adopt a square antiprismatic structure. The β polymorph gradually converts to α at 130 °C.

Monomeric UF₅

Of theoretical interest, molecular UF₅ can be generated as a transient monomer by UV-photolysis of uranium hexafluoride. It is thought to adopt a square pyramidal geometry.

File:UF5 monomer.png

Structure of molecular UF₅.