The structure of gold(V) fluoride in the solid state is centrosymmetric 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; 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).[1] 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; and is also the strongest known Lewis acid.[1]
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 hexafluoroaurate:[2][3]
Au(s) + O2(g) + 3 F2(g) → O2AuF6(s)
This salt decomposes at 180 °C to produce the pentafluoride:
^Emeléus, H. J.; Sharpe, A. G. (1983). Advances in Inorganic Chemistry and Radiochemistry. Academic Press. p. 83. ISBN0-12-023627-3.
^W. Henderson (2000). Main group chemistry. Great Britain: Royal Society of Chemistry. p. 149. ISBN0-85404-617-8.
^Charlie Harding; David Arthur Johnson; Rob Janes (2002). Elements of the p block. Great Britain: Royal Society of Chemistry. p. 94. ISBN0-85404-690-9.