Pt as the limit of high oxidation states in oxide-nitride species

A series of pentaatomic species has been investigated theoretically with relativistic DFT using the M06-L functional with both ZORA scalar relativistic correction, and including spin-orbit coupling effects. The distorted quasi-octahedral local minima for PtNO 3 + , PtN 2 O 2 and PtN 3 O − corresponding to decavalent Pt were found to be unstable with respect to the elimination of O 2 , NO or N 2 . However, barriers surrounding these minima suggest that these species could be achieved under low-temperature conditions, similar to what was predicted for PtO 4 2+ dications. Decavalent platinum sets the upper limit for high oxidation states of the chemical elements. Neutral PtO 2 N 2 and PtNO 3 + and PtN 3 O − ions are theoretically predicted to be sufficiently metastable to be prepared by a skillful experimenter in cryogenic conditions. PtNO 3 + has a longer lifetime than the previously claimed PtO 4 2+ .