Magnetic Couplings in Edge-Sharing High-Spin d⁷ Compounds

High-spin d⁷ Co(II) compounds have recently been identified as possible platforms for realising highly anisotropic and bond-dependent couplings featured in quantum-compass models such as the celebrated Kitaev model. In order to evaluate this potential, we consider all symmetry-allowed contributions to the magnetic exchange for ideal edge-sharing bonds. Through a combination of ab-initio calculations we conclude that bond-dependent couplings are generally suppressed in favor of Heisenberg or XXZ exchange for real materials. Consequences for prominent Co(II) materials will be discussed.