Platinum hexafluoride
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| Platinum hexafluoride | |
|---|---|
 |
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| IUPAC name | Platinum hexafluoride |
| Other names | Platinum(VI) fluoride |
| Properties | |
| Molecular formula | PtF6 |
| Molar mass | 309.1 |
| Appearance | red |
| Density | 5.21 |
| Melting point |
61.3 °C[1] |
| Boiling point |
69.1 °C[1] |
| Hazards | |
| Main hazards | oxidizer |
| Flash point | n.a. |
| Autoignition temperature |
n.a. |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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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)−, dioxygen hexafluoroplatinate.
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[edit] Synthesis
PtF6 was first prepared by reaction of fluorine with platinum metal.[2] This route remains the method of choice.[3]
- Pt + 3 F2 → PtF6
PtF6 can also be prepared by disproportionation of PtF5. The required PtF5 can be obtained by fluorinating PtCl2
- PtCl2 + 2.5 F2 → PtF5 + Cl2
- 2 PtF5 → PtF6 + PtF4
[edit] 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.[3]
[edit] References
- ^ a b Perry, Dale L. and Sidney L. Phillips. Handbook of Inorganic Compounds. CRC Press, 1995. ISBN 0849386713. Google Book Search Result
- ^ 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
- ^ 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
[edit] General reading
- Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
