A first‐principles study on the existence and structures of the lighter alkaline‐earth pernitrides

The lighter alkaline‐earth pernitrides BeN₂, MgN and CaN₂ have been structurally predicted by a series of density‐functional (GGA/PBE/PAW) electronic‐structure calculations. Despite their crystal chemistry clearly pointing towards the formulation M²⁺N₂^2? with an N? N distance of 1.26 Å, all phases turn out as metallic compounds which are exothermic with respect to the elements. The M²⁺ coordination numbers are a simple function of the cationic radius. The bulk moduli are about three times smaller than those of the noble‐metal pernitrides, a consequence of the smaller anionic charge in the former phases. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010