On all three monolayers, Non-Equivalent configuration Non-Equivalent-XM forms the same structure as the configuration S-Neighbouring-M on WS 2 . The metal-metal interaction energy for these Non-Equivalent-XM clusters are identical on all three monolayers. The binding energy follows the same stability trend as single atom adsorption, due to the metal-substrate interaction energies being largest on WTe 2 and smallest on WSe 2 .