Iridium hexafluoride

Iridium hexafluoride, also iridium(VI) fluoride, (IrF₆) is a compound of iridium and fluorine and one of the seventeen known binary hexafluorides. It is one of only a few compounds with iridium in the oxidation state +6.

Iridium hexafluoride

Names
IUPAC name iridium(VI) fluoride
Other names iridium hexafluoride
Identifiers
CAS Number	7783-75-7 Y
3D model (JSmol)	Interactive image
ChemSpider	10323846
ECHA InfoCard	100.029.113
PubChem CID	3014587
UNII	UP14U33TGX Y
InChI InChI=1S/6FH.Ir/h6*1H;/q;;;;;;+6/p-6 Key: JQAZQSHUPWSSPF-UHFFFAOYSA-H InChI=1/6FH.Ir/h6*1H;/q;;;;;;+6/p-6/rF6Ir/c1-7(2,3,4,5)6 Key: JQAZQSHUPWSSPF-VYYYRSGCAJ
SMILES F[Ir](F)(F)(F)(F)F
Properties
Chemical formula	IrF6
Molar mass	306.22 g/mol
Appearance	yellow crystalline solid[1]
Density	5.11g/mL[2]
Melting point	44 °C (111 °F; 317 K)[1]
Boiling point	53.6 °C (128.5 °F; 326.8 K)[1]
Solubility	soluble in HF
Related compounds
Other cations	rhodium hexafluoride osmium hexafluoride platinum hexafluoride
Related compounds	iridium(V) fluoride
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

Synthesis

Iridium hexafluoride is made by a direct reaction of iridium metal in an excess of elemental fluorine gas at 300 °C. However, it is thermally unstable and must be frozen out of the gaseous reaction mixture to avoid dissociation.

Ir + 3 F
₂ → IrF
₆

Description

Iridium hexafluoride is a yellow crystalline solid that melts at 44 °C and boils at 53.6 °C.^[1] The solid structure measured at −140 °C is orthorhombic space group Pnma. Lattice parameters are a = 9.411 Å, b = 8.547 Å, and c = 4.952 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 5.11 g·cm⁻³.^[2]

The IrF₆ molecule itself (the form important for the liquid or gas phase) has octahedral molecular geometry, which has point group (O_h). The Ir–F bond length is 1.833 Å.^[2]

Calculations suggest that fluorine might react with iridium hexafluoride at 39 GPa to form IrF₈.^[3]

References

1. CRC Handbook of Chemistry and Physics, 90th Edition, CRC Press, Boca Raton, Florida, 2009, ISBN 978-1-4200-9084-0, Section 4, Physical Constants of Inorganic Compounds, p. 4-85.
2. T. Drews, J. Supeł, A. Hagenbach, K. Seppelt: "Solid State Molecular Structures of Transition Metal Hexafluorides", in: Inorganic Chemistry, 2006, 45 (9), S. 3782–3788; doi:10.1021/ic052029f; PMID 16634614.
3. Lin, Jianyan; Zhao, Ziyuan; Liu, Chunyu; Zhang, Jing; Du, Xin; Yang, Guochun; Ma, Yanming (2019-03-13). "IrF8 Molecular Crystal under High Pressure". Journal of the American Chemical Society. 141 (13). American Chemical Society (ACS): 5409–5414. doi:10.1021/jacs.9b00069. ISSN 0002-7863. PMID 30864432. S2CID 76664353.

Further reading

• Gmelins Handbuch der anorganischen Chemie, System Nr. 67, Iridium, Supplement Volume 2, pp. 99–102.

External links

• Iridium hexafluoride at webelements.com.