The Vienna Ab-initio Software Package (VASP) [1] along with the Perdew-Burke-Eznerhof (PBE) [2] exchangecorrelation functional was used to perform all density functional theory (DFT) calculations for calculating energy and forces of clusters in the training and validation datasets. The projector-augmented wave (PAW) potentials used in these calculations are summarised in Table . A single k-point at the center of the Brillouin zone (gamma point) was used for each calculation. The convergence criteria for the electronic self-consistent iteration and the ionic relaxation loop were set to be 0.1 meV and 1 meV per cluster, respectively. The ground state bulk structures for the elements were collected from the Materials Project database [3]. A dense k-point mesh, (n atoms × n kpoints ≈ 1000) was used for the DFT calculations that were used to calculate the cohesive energies and lattice parameters. A relatively high tolerance of 10 -6 eV for energy convergence was employed for the same.