Dinitrogen activation with Ca

N₂, one of the most stable strongly bound molecules known, is hard to activate. We found that not only transition metals but also simply Ca can do this. To what extent d-orbitals play a role is controversial. The oxidation state of Ca in this complex is +II but it reacts as a synthon for the highly reactive Ca(+I) complex.

Science 2021, 371, 1125
Dinitrogen complexation and reduction at low-valent calcium
DOI: 10.1126/science.abf2374