Impacts on global climate and environmental decay are increasingly evident as consequences of human activities . Mitigating these effects will ultimately be underpinned by the transition to sustainable means of energy harvesting and consumption, within which electrochemical technologies stand to play a critical role . Widespread adoption of electrochemical water and CO2 reduction to form H2 or C-based fuels is hampered by the kinetics of the oxygen evolution reaction (OER) and thus, much work in the field is dedicated towards OER catalyst discovery 5 . To this end, mixed-metal oxides have emerged as the top class of materials for this reaction in alkaline conditions . The recent decade of work in the field has yielded important gains in understanding the roles of incorporating Fe impurities, lattice strain, substrate effects, interfaces and exfoliation. In an orthogonal direction, the modification of the catalytically active sites through hetero-element incorporation has yielded substantial gains in performance over purely Ni/Co/Fe oxides, though most efforts focus on cationic incorporation . In contrast, anionic incorporation is seldom used, largely due to synthetic challenges, especially in the direction of fluoride substitution. However, initial reports suggest that hetero-anionic compounds hold much promise as OER catalysts, though the factors driving these observations are not fully settled . Often, metal oxides catalyze the OER through sequential proton-coupled electron transfer steps. This inevitably limits their performance via scaling relations as all intermediates share a M-O bond. Breaking these scaling relations for enhanced OER performance can be accomplished by accessing new reaction mechanisms such as radical oxygen coupling and lattice oxygen involvement, and the discovery of new OER catalyst compositions ultimately underpins access to such reaction pathways.