Gold(V) fluoride
Encyclopedia
Gold fluoride is the inorganic compound
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 with the formula Au2F10. This fluoride
Fluoride
Fluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...

 compound features gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

 in its highest known oxidation state
Oxidation state
In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

. This red solid dissolves in hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...

 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
Octahedral molecular geometry
In chemistry, octahedral molecular geometry describes the shape of compounds where in six atoms or groups of atoms or ligands are symmetrically arranged around a central atom, defining the vertices of an octahedron...

 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
Antimony pentafluoride
Antimony pentafluoride is the inorganic compound with the formula SbF5. This colourless, viscous liquid is a valuable Lewis acid and a component of the superacid fluoroantimonic acid, the strongest known acid...

.

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
Dioxygenyl
The dioxygenyl ion, O2+, is a rarely encountered oxycation in which both oxygen atoms have a formal oxidation state of +½. It is formally derived from oxygen by the removal of an electron:...

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
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