Magnesium amidoborane monoammoniate: Plane-wave DFT calculations

Recently it has been reported that magnesium amidoborane monoammoniate ( Mg ( NH 2 BH 3 ) 2 · NH 3 ) has a high hydrogen content and consequently is an attractive candidate for hydrogen storage applications. The electronic and structural properties of the amidoborane Mg ( NH 2 BH 3 ) 2 · NH 3 have been calculated within the generalized gradient approximation (GGA) in the Perdew–Burke–Ernzerhof (PBE) parameterization. The role of the ammonia ligand is to stabilize magnesium amidoborane ( Mg ( NH 2 BH 3 ) 2 ) by increasing the number of H ⋯ H contacts. The band gap of the GGA-PBE relaxed structure is computed using the conventional density functionals and the semiempirical hybrid functional approach HSE06. It is shown that this compound is an insulator with a gap size of between 4.6 and 6.4 eV. These calculations reveal the covalent nature of N–H and B–H bonds. The interaction character between Mg and N atoms is essentially ionic.