Ab initio calculations were performed using the Vienna Ab Initio Simulation Package (VASP) for the candidates. Density functional theory (DFT) implementing the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) function was used in each case. Spin polarization and magnetism was considered. All VASP input files for the structure optimization were automatically generated by pymatgen "io.vasp.sets" module with the default parameters provided by Materials Project. Bader charge analysis was performed to identify the electron distribution of the partial charge density within 0.2 eV around Fermi Energy level. Finally, we use Bader charge analysis to identify maxima in electron density 2.2 Å or more away from the nearest atom. Where present we consider the candidates as electrides, which was found to be effective in this regard in a previous study. 2