Crystalline, Electronic, and Vibrational Structures of Zinc Cyanides

A model of ZnCN₂ crystal with classical chalcopyrite structure is considered within density functional theory. The obtained equilibrium lattice parameters are a = 4.2395 Å and c = 6.5258 Å, the tetragonal compression is γ = 1.539, and the anion displacement is u = 0.346. The electronic structure, optical frequencies, and elastic constants are calculated for the simulated crystal ZnCN₂ and for its isostructural analogue Zn(CN₂). Some features of the electronic structure, vibrational modes, and chemical bonding are shown to result from the short-range order in the studied cyanides.