Understanding gold chemistry through relativity

Gold chemistry is briefly reviewed indicating areas where a consideration of relativistic effects has led to major advances in the understanding of the special role of gold among the elements in the periodic table. On this basis, the unique properties of gold atoms and clusters, bulk gold and its surface, molecular and supramolecular compounds of gold, with aurophilic interactions, can be qualitatively rationalized or even quantitatively reproduced. A few complementary illustrative examples are given, where aurophilic bonding is instrumental in promoting auration of weakly acidic hydrocarbons XYCH2 to give dimetallated compounds XYC(AuL)2, the structures of which show intimate interactions in the triangular CAu2 unit.