Gimferrer, MartiDanes, SergiVos, EvaYıldız, Cem BurakCorral, InesJana, AnukulSalvador, PedroAndrada, Diego M.2022-06-272022-06-2720222041-65202041-6539https:/dx.doi.org/10.1039/d2sc01401ghttps://hdl.handle.net/20.500.12451/9484Low-valent group 2 (E = Be and Mg) stabilized compounds have been long synthetically pursued. Here we discuss the electronic structure of a series of Lewis base-stabilized Be and Mg compounds. Despite the accepted zero(0) oxidation state nature of the group 2 elements of some recent experimentally accomplished species, the analysis of multireference wavefunctions provides compelling evidence for a strong diradical character with an oxidation state of +2. Thus, we elaborate on the distinction between a description as a donor-acceptor interaction L(0) ? E(0) reversible arrow L(0) and the internally oxidized situation, better interpreted as a diradical L(-1) -> E(+2) <- L(-1) species. The experimentally accomplished examples rely on the strengthened bonds by increasing the pi-acidity of the ligand; avoiding this interaction could lead to an unprecedented low-oxidation state.eninfo:eu-repo/semantics/closedAccessBondComplexesDefinitionOrbitalsLigandsMgArticle13226583659110.1039/d2sc01401g35756523Q1WOS:000797579700001Q1