Ag2S2O8 meets AgSO4: the second example of metal–ligand redox isomerism among inorganic systems

Tomasz E. Gilewski, Piotr J. Leszczyński, Armand Budzianowski, Zoran Mazej, Adam Grzelak, Tomasz Jaroń and  Wojciech Grochala

Dalton Transactions, 2016,45, 18202-18207
DOI: 10.1039/C6DT03283D
Received 19 Aug 2016, Accepted 09 Oct 2016
First published online 31 Oct 2016

This work commemorates 120th birth anniversary of Gilbert N. Lewis and the centennial of his „octet rule” paper.


Valence (redox) isomerism based on electron exchange between a metal and a ligand is immensely rare in purely inorganic systems, with only one documented case, that of PbS2 which adopts two polymorphic forms corresponding to Pb(IV)(S2−)2 and Pb(II)(S22−). Here we have taken advantage of metathetic reactions using salts of weakly coordinating anions and we have prepared for the first time Ag(I)2S2O8, silver(I) peroxydisulphate. The title compound crystallizes in the non-centrosymmetric Cc space group with partial disorder of the anionic sublattice. Ag(I)2S2O8 is a highly thermally unstable diamagnetic and colourless valence isomer of the antiferromagnetic and black Ag(II)SO4, described by us in the past.