On the Extreme Oxidation States of Iridium

Abstract

It has recently been suggested that the oxidation states of Ir run from the putative -III in the synthesized solid Na3 [Ir(CO)3 ] to the well-documented +IX in the species IrO4 (+) . Furthermore, [Ir(CO)3 ](3-) was identified as an 18-electron species. A closer DFT study now finds support for this picture: The orbitals spanned by the 6s,6p,5d orbitals of the iridium are all occupied. Although some have considerable ligand character, the deviations from 18 e leave the orbital symmetries unchanged. The isoelectronic systems from Os(-IV) to Au(-I) behave similarly, suggesting further possible species. To paraphrase Richard P. Feynmann "there is plenty of room at the bottom".

Oxidation State 10 Exists

“…by time‐of‐flight photodissociation spectroscopy . (As discussed previously, good experimental Mössbauer isomer shift evidence already existed for Ir IX in 1969; Ref. was the first to produce Ir IX by chemical, as opposed to nuclear, means.)…”

Oxidation State 10 Exists

“…This was confirmed in 2014 by Wang et al by matrix-isolation experiments. [5] (As discussed previously, [2,4,6] good experimental Mçssbauer isomer shift evidence already existed [7] for Ir IX in 1969; Ref. [5] was the first to produce Ir IX by chemical, as opposed to nuclear, means.)…”

Developments in Platinum-Group Metals as Dual Antibacterial and Anticancer Agents

“…Iridium is a d-block transition metal with a symbol of Ir, atomic number of 77, and atomic mass of 192.217 [11]. Iridium has variable oxidation states from − III to +IX [14], but according to Liu et al, iridium has four different oxidation states, namely, +1, +2, +3, and +4. [15].…”