Electronic structure and chemical bond in KN3 and KSCN crystals

Crystal structure parameters, band spectra, distribution maps of the toal and partial electron densities of KN₃ and KSCN are calculated from the first principles using the density functional method and the general properties and distinctions in the band spectra are analyzed. The groups of balance subbands are qualitatively similar; in the upper valence band of KN₃ there is weak hybridization of p states of the complex anion and metal, which is not observed in KSCN. KSCN crystals are direct band gap materials and KN₃ are indirect band gap materials. The existence of weak covalent bonding of complex anions with metal is found from the electron density distribution maps in both crystals and also between metal atoms in KSCN, which is absent in KN₃.