Density functional theory (DFT) calculations may, therefore, guide synthesis efforts of the proposed candidates. Still, care must be taken with DFT calculations to handle the highenergy but spatially shielded 4f electrons of europium appropriately. Including 4f electrons in the valence can reduce transferability while increasing the necessary kinetic energy cutoff. Freezing the 4f electrons in the core eliminates these issues and, despite eliminating the magnetic contribution, has shown promise in modeling known lanthanide systems. If 4f electrons are frozen in the core, separate pseudopotentials are needed for divalent (4f 7 core) and trivalent (4f 6 core) europium. Starting with tests of DFT parameters and a set of proposed candidates, DFT stability calculations can provide a practical number of compounds to explore experimentally.