A linear cobalt(II) complex with maximal orbital angular momentum from a non-Aufbau ground state

Cobalt unfettered by its ligand field Applied magnetic fields induce a field in any compound with unpaired electrons. However, for the induced field to persist once the applied field is gone, the electrons must be configured to manifest orbital angular momentum. Generally, the influence of ligands severely restricts that property in transition metal complexes. Bunting et al. now show that a cobalt ion is just barely affected by two linearly coordinated carbon ligands and, as such, exhibits maximal orbital angular momentum. Although its magnetic properties mainly pertain at very low temperature, its structure offers a more general design principle. Science , this issue p. eaat7319