Platinum hexafluoride

Platinum hexafluoride
Identifiers
ChemSpider 21106464 Y
Jmol-3D images Image 1
Properties
Molecular formula PtF6
Molar mass 309.07 g/mol
Appearance dark-red crystals
Density 3.83 g/cm3
Melting point

61.3 °C

Boiling point

69.14 °C

Solubility in water reacts violently
Structure
Crystal structure Orthorhombic, oP28
Space group Pnma, No. 62
Coordination
geometry
octahedral (Oh)
Dipole moment 0
Hazards
Main hazards oxidizer
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Platinum hexafluoride is the chemical compound with the formula PtF6. It is a dark-red volatile solid that forms a red gas. The compound is a unique example of platinum in the +6 oxidation state. With only four d-electrons, it is paramagnetic with a triplet ground state.

PtF6 is a strong oxidant and a strong fluorinating agent that is best known for its reaction with xenon to form "XePtF6," known as xenon hexafluoroplatinate. The discovery of this reaction in 1962 proved that noble gases form chemical compounds. Previous to the experiment with xenon, PtF6 had been shown to react with oxygen to form (O2)+(PtF6), dioxygenyl hexafluoroplatinate.

Contents

Synthesis

PtF6 was first prepared by reaction of fluorine with platinum metal.[1] This route remains the method of choice.[2]

Pt + 3 F2 → PtF6

PtF6 can also be prepared by disproportionation of PtF5. The required PtF5 can be obtained by fluorinating PtCl2:

2 PtCl2 + 5 F2 → 2 PtF5 + 2 Cl2
2 PtF5 → PtF6 + PtF4

Other hexafluoride compounds

The neutral hexafluorides of other elements are also volatile. These include osmium, iridium, rhodium, ruthenium, rhenium, tungsten, technetium, and uranium. All are aggressive oxidants. Uranium hexafluoride and tungsten hexafluoride are used in the nuclear and microelectronics industries, respectively. In the main group elements, sulfur, xenon, selenium, and tellurium form isolable hexafluorides. Sulfur hexafluoride is so extremely stable, perhaps due to steric effects, that it is used as an inert fluid in transformers. The analogues selenium hexafluoride and tellurium hexafluoride are, however, strongly reactive.

Like the hexafluorides of Mo, Tc, Ru, Rh, W, Re, Os, and Ir, PtF6 is octahedral in both the solid state and in the gaseous state. The Pt-F bond lengths are 185 picometers.[2]

References

  1. ^ Weinstock, B.; Claassen, H. H.; Malm, J. G. “Platinum Hexafluoride” Journal of the American Chemical Society 1957, volume 79, pp 5832 - 5832. doi:10.1021/ja01578a073
  2. ^ a b Drews, T.; Supel, J.; Hagenbach, A.; Seppelt, K. “Solid State Molecular Structures of Transition Metal Hexafluorides” Inorganic Chemistry 2006, volume 45, pp 3782-3788.doi:10.1021/ic052029f

General reading