Osmium hexafluoride

Osmium hexafluoride, also osmium(VI) fluoride, (OsF₆) is a compound of osmium and fluorine, and one of the seventeen known binary hexafluorides.

Osmium hexafluoride

Unit cell of osmium hexafluoride.
Names
IUPAC name osmium(VI) fluoride
Other names osmium hexafluoride
Identifiers
CAS Number	13768-38-2 Y
3D model (JSmol)	Interactive image
ChemSpider	109930
ECHA InfoCard	100.033.969
PubChem CID	123327
UNII	1G36E253R5 Y
CompTox Dashboard (EPA)	DTXSID50160269
InChI InChI=1S/6FH.Os/h6*1H;/q;;;;;;+6/p-6 Key: MLKFZZUUYQWFMO-UHFFFAOYSA-H InChI=1/6FH.Os/h6*1H;/q;;;;;;+6/p-6/rF6Os/c1-7(2,3,4,5)6 Key: MLKFZZUUYQWFMO-ZXTFGAQLAX
SMILES F[Os](F)(F)(F)(F)F
Properties
Chemical formula	OsF6
Molar mass	304.22 g/mol
Appearance	yellow crystalline solid[1]
Density	5.09g/mL[2]
Melting point	33.4 °C (92.1 °F; 306.5 K)[1]
Boiling point	47.5 °C (117.5 °F; 320.6 K)[1]
Structure
Space group	Pnma, No. 62
Lattice constant	a = 938.7 pm, b = 854.3 pm, c = 494.4 pm[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Osmium hexafluoride is made by a direct reaction of osmium metal exposed to an excess of elemental fluorine gas at 300 °C.

Os + 3 F
₂ → OsF
₆

Description

Osmium hexafluoride is a yellow crystalline solid that melts at 33.4 °C and boils at 47.5 °C.^[1] The solid structure measured at −140 °C is orthorhombic space group Pnma. Lattice parameters are a = 9.387 Å, b = 8.543 Å, and c = 4.944 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 5.09 g·cm⁻³.^[2]

The OsF₆ molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group (O_h). The Os–F bond length is 1.827 Å.^[2]

Partial hydrolysis of OsF₆ produces OsOF₄.^[4]