Hg2NF, Analogue of HgO

Substitution of aliovalent anions in metal oxides imparts significant changes to the electronic structure of the materials. We have been able to fully substitute N3- and F- in place of O2- to obtain Hg2NF. Hg2NF is isostructural with orthorhombic HgO (mineral montroydite). The bond lengths of Hg2NF obtained by Rietveld refinement are dissimilar and the optical band gap of Hg2NF (2.56 eV) is higher than that of HgO (2.2 eV). The elemental composition of Hg, N, and F were obtained by X-ray photoelectron spectroscopy and found to be 2:1:1. First-principles calculations show Hg2NF to be a direct band gap semiconductor with the valence band consisting mainly of N (2p) orbitals. The conduction band minimum (CBM) has a mixed contribution from Hg-6s and N-2p orbitals. The lowest energy band has a dominant contribution from Hg-5d states in all the configurations.