Based on the DFT, calculations were performed within the Vienna Ab initio Simulation Package (VASP) code and the Projector Augmented Wave (PAW) method for the atomic potentials. DFT exchange correlation (XC) effects were considered using the generalized gradient approximation (GGA) . Preliminary calculations with the native DFT-XC local density approximation (LDA) resulted in underestimated lattice constants at ambient pressure and were therefore abandoned. Relaxation of the atoms to the ground state structures was performed with the conjugate gradient algorithm according to Press et al. . The Blöchl tetrahedron method with corrections according to the Methfessel and Paxton scheme was used for geometry optimization and energy calculations, respectively. Brillouin-zone (BZ) integrals were approximated by a special k-point sampling according to Monkhorst and Pack . Structural parameters were optimized until atomic forces were below 0.02 eV/Å and all stress components were < 0.003 eV/Å 3 . The calculations were converged at an energy cutoff of 400 eV for the plane-wave basis set in terms of the k-point integration in the reciprocal space from k x (6)×k y (6)×k z (6) up to k x ×k y ×k z to obtain a final convergence and relaxation to zero strains for the original stoichiometries presented in this work. In the post-processing of the ground state electronic structures, the charge density projections were operated on the lattice sites.