Gold(V) fluoride is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the formula Au
2F
10. This
fluoride
Fluoride (). According to this source, is a possible pronunciation in British English. is an inorganic, monatomic anion of fluorine, with the chemical formula (also written ), whose salts are typically white or colorless. Fluoride salts typ ...
compound features
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
in its highest known
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
. This red solid dissolves in
hydrogen fluoride
Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...
but these solutions decompose, liberating fluorine.
The structure of gold(V) fluoride in the solid state is
centrosymmetric
In crystallography, a centrosymmetric point group contains an inversion center as one of its symmetry elements. In such a point group, for every point (x, y, z) in the unit cell there is an indistinguishable point (-x, -y, -z). Such point groups ...
with hexacoordinated gold and an
octahedral arrangement of the fluoride centers on each gold center. It is the only known dimeric pentafluoride, although sulfur can form
disulfur decafluoride
Disulfur decafluoride is a chemical compound with the formula . It was discovered in 1934 by Denbigh and Whytlaw-Gray. Each sulfur atom of the molecule is octahedral, and surrounded by five fluorine atoms and one sulfur atom. The two sulfur ato ...
; other pentafluorides are monomeric (
P,
As,
Sb,
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 82:18 has been observed.
Gold pentafluoride is the strongest known fluoride ion acceptor, exceeding the acceptor tendency of even
antimony pentafluoride
Antimony pentafluoride is the inorganic compound with the formula Sb F5. This colourless, viscous liquid is a valuable Lewis acid and a component of the superacid fluoroantimonic acid, formed when mixing liquid HF with liquid SbF5 in a 2:1 ratio. ...
.
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
dioxygenyl
The dioxygenyl ion, , is a rarely-encountered oxycation in which both oxygen atoms have a formal oxidation state of . It is formally derived from oxygen by the removal of an electron:
:O2 → + e−
The energy change for this process is call ...
hexafluoroaurate:
:Au(s) + O
2(g) + 3 F
2(g) → O
2AuF
6(s)
This salt decomposes at 180 °C to produce the pentafluoride:
: 2 O
2AuF
6(s) → Au
2F
10 (s) + 2 O
2(g) + F
2(g)
Krypton difluoride
Krypton difluoride, KrF2 is a chemical compound of krypton and fluorine. It was the first compound of krypton discovered. It is a volatile, colourless solid at room temperature. The structure of the KrF2 molecule is linear, with Kr−F distances ...
can also oxidise
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
to the +5 oxidation state:
: 7 (g) + 2 Au (s) → 2 KrFAuF (s) + 5 Kr (g)
KrFAuF decomposes at 60 °C into gold(V) fluoride and gaseous krypton and fluorine:
:2 KrFAuF → (s) + 2 Kr (g) + 2 (g)
References
{{Fluorine compounds
Fluorides
Metal halides
Gold compounds
Gold–halogen compounds