Structural properties and bonding nature of 3-methyl-4-phenyl-5-(2-pyridyl)-1,2,4-triazole single crystal

The atomic positions of 3-methyl-4-phenyl-5-(2-pyridyl)-1,2,4-triazole single crystal taken from the Xray diffraction data obtained by Liu et al. [1] were optimized by minimization of the forces acting on the atoms using a full potential linear augmented plane wave method within density-functional theory. The local density approximation (LDA) by Ceperley-Alder (CA) exchange-correlation potential was applied. The full potential calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at P point of the Brillouin zone resulting in a direct energy gap of 3.4 eV for the original experimental structure and 3.2 eV for the optimized structure. The upper VB is formed mainly by C, H. and N atoms while the lower CB has mainly C and H atoms. We present an analysis of the partial densities of states which gives useful information on hybridization and the orbital character of the states. We have calculated the bond lengths and angles, a good agreement with the experimental data were found. The origin of the chemical bonding and the electronic charge density contour in the (1 0 0) and (1 1 0) planes were analyzed. (C) 2011 Elsevier B.V. All rights reserved.