Transition metal thiosulfate complex

Thiosulfate occurs in nature and is used industrially, so its interactions with metal ions are of some practical interest.

A typical complex is [Pd(S2O3)2(ethylenediamine)]2−, which features a pair of S-bonded thiosulfate ligands.

[2] In some cases, they arise by oxidation of polysulfido complexes, or by binding of sulfur trioxide to sulfido ligands.

The dissolution process entails reactions involving the formation of 1:2 and 1:3 complexes (X = halide):[6] Fixation involves these chemical reactions (X = halide, typically Br−):[7] Sodium thiosulfate and ammonium thiosulfate have been proposed as alternative lixiviants to cyanide for extraction of gold from ores[8] and printed circuit boards.

[8] In the IUPAC Red Book the following terms may be used for thiosulfate as a ligand: trioxido-1κ3O-disulfato(S—S)(2−); trioxidosulfidosulfato(2−); thiosulfato; sulfurothioato.