Rhenium hexafluoride

Rhenium hexafluoride
Names
	IUPAC name rhenium(VI) fluoride
	Other names rhenium hexafluoride
Identifiers
CAS Number	10049-17-9;
3D model ( JSmol)	Interactive image;
ECHA InfoCard	100.030.144
EC Number	233-172-2;
PubChem CID	66231;
UNII	U1FW6E300T ;
CompTox Dashboard (EPA)	DTXSID8064931 ;
	InChI InChI=1S/6FH.Re/h6*1H;/q;;;;;;+6/p-6;
	SMILES F[Re](F)(F)(F)(F)F;
Properties
Chemical formula	F6Re
Molar mass	300.20 g/mol
Appearance	liquid, or yellow crystalline solid
Density	4.94g/mL
Melting point	18.5 °C (65.3 °F; 291.6 K)
Boiling point	33.7 °C (92.7 °F; 306.8 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Rhenium hexafluoride, also rhenium(VI) fluoride, (ReF₆) is a compound of rhenium and fluorine and one of the seventeen known binary hexafluorides.

Chemistry

Rhenium hexafluoride is made by combining rhenium heptafluoride with additional rhenium metal at 300 °C in a pressure vessel.^[2]

6 ReF
₇ + Re → 7 ReF
₆

The compound is a Lewis acid and strong oxidant, adducting potassium fluoride and oxidizing nitric oxide to nitrosyl:^[3]

2KF + ReF₆ → K₂ReF₈

NO + ReF₆ → [NO][ReF₆]

Description

Rhenium hexafluoride is a liquid at room temperature. At 18.5 °C, it freezes into a yellow solid. The boiling point is 33.7 °C.^[1]

The solid structure measured at −140 °C is orthorhombic space group Pnma. Lattice parameters are a = 9.417 Å, b = 8.570 Å, and c = 4.965 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 4.94 g·cm⁻³.^[2]

The ReF₆ molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group (O_h). The Re–F bond length is 1.823 Å.^[2]