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Gold(V) fluoride

Names
IUPAC name Gold(V) fluoride
Other names gold pentafluoride
Identifiers
CAS Number	57542-85-5
CompTox Dashboard (EPA)	DTXSID101045547
Properties
Chemical formula	AuF5
Molar mass	291.959 g/mol
Appearance	red unstable solid
Melting point	60 °C (Decomposes)
Solubility in water	Decomposes
Structure
Crystal structure	orthorhombic (Pnma)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Corrosive, toxic
Related compounds
Other cations	SbF5, BrF5, IF5
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Gold(V) fluoride is the inorganic compound with the formula Au₂F₁₀. This fluoride compound features gold in its highest known oxidation state. This red solid dissolves in hydrogen fluoride but these solutions decompose, liberating fluorine.

The structure of gold(V) fluoride in the solid state is centrosymmetric with hexacoordinated gold and an octahedral arrangement of the fluoride centers around each gold center. It is the only known dimeric pentafluoride; other pentafluorides are monomeric (P, As, Cl, Br, I), tetrameric (Nb, Ta, Cr, Mo, W, Tc, Re, Ru, Os, Rh, Ir, Pt), or polymeric (Bi, V, U). In the gas phase, a mixture of dimer and trimer in the ratio 82:12 has been observed.

Gold pentafluoride is the strongest known fluoride ion acceptor, exceeding the acceptor tendency of even antimony pentafluoride.

Synthesis

Gold(V) fluoride can be synthesized by heating gold metal in an atmosphere of oxygen and fluorine to 370 °C at 8 atmospheres to form gold dioxygenyl fluoride:

2 Au + 2 O₂ + 6 F₂ → 2 O₂AuF₆

This salt decomposes at 180 °C to produce the pentafluoride:

2 O₂AuF₆ → Au₂F₁₀ + 2 O₂ + F₂

References

1. In-Chul Hwang, Konrad Seppelt "Gold Pentafluoride: Structure and Fluoride Ion Affinity" Angewandte Chemie International Edition 2001, volume 40, 3690-3693. doi:10.1002/1521-3773(20011001)40:19<3690::AID-ANIE3690>3.0.CO;2-5
2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
3. Emeléus, H. J.; Sharpe, A. G. (1983). Advances in Inorganic Chemistry and Radiochemistry. Academic Press. p. 83. ISBN 0120236273.

• Fluorides
• Gold compounds