Limits of stability for compounds of pentavalent praseodymium

Eleven possible candidates for compounds of pentavalent praseodymium were investigated with relativistic density functional theory using the B3LYP functional with ZORA scalar relativistic correction and including spin orbit coupling effects. Two of those candidates had previously been synthesized and another two of them were previously theoretically predicted. Three new species were proposed here as possible candidates for the compounds of Pr in its fifth oxidation state: PrF4+, PrO2F2- and PrOF2+. The main technical obstacle in synthesizing these ions is their high reactivity due to large electron affinity; decomposition via bimolecular reaction pathways and low energy of excitation to the triplet state constitute other stability limiting factors.