A novel square planar N_(4)^(2-)ring with aromaticity in BeN_(4)

摘要

A structural search leads to the prediction of a novel alkaline earth nitride BeN_(4)containing a square planar N_(4)^(2-)ring.This compound has a particular chemical bonding pattern giving it potential as a high-energy-density material.The P4/nmm phase of BeN_(4)may be stable under ambient conditions,with a bandgap of 3.72 eV.It is predicted to have high thermodynamic and kinetic stability due to transfer of the outer-shell s electrons of the Be atom to the N_(4)cluster,with the outer-shell 2p orbital accommodating the lone-pair electrons of N_(4)^(2-).The total of sixπelectrons is the most striking feature,indicating that the square planar N_(4)^(2-)exhibits aromaticity.Under ambient conditions,BeN_(4)has a high energy density(3.924 kJ/g relative to Be3N2 and N2 gas),and its synthesis might be possible at pressures above 31.6 GPa.