Recently it has been reported that magnesium amidoborane monoammoniate (Mg(NH2BH3)(2) center dot NH3) has a high hydrogen content and consequently is an attractive candidate for hydrogen storage applications. The electronic and structural properties of the amidoborane Mg(NH2BH3)(2) center dot NH3 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(NH2BH3)(2)) by increasing the number of H center dot center dot center dot 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. (C) 2012 Elsevier B. V. All rights reserved.