Revisiting the Solution Structure of Ceric Ammonium Nitrate

Abstract

Abstract Ceric ammonium nitrate (CAN) is a single‐electron‐transfer reagent with unparalleled utility in organic synthesis, and has emerged as a vital feedstock in diverse chemical industries. Most applications use CAN in solution where it is assigned a monomeric [Ce IV (NO 3 ) 6 ] 2− structure; an assumption traced to half‐century old studies. Using synchrotron X‐rays and Raman spectroscopy we challenge this tradition, converging instead on an oxo‐bridged dinuclear complex, even in strong nitric acid. Thus, one equivalent of CAN is recast as a two‐electron‐transfer reagent and a redox‐activated superbase, raising questions regarding the origins of its reactivity with organic molecules and giving new fundamental insight into the stability of polynuclear complexes of tetravalent ions.