Unlike Neighbouring configurations, Cu atoms do not migrate for the Separated adsorption modes. Across all three monolayers, Separated adsorption configurations follow the trends seen in the single atom configurations, where Cu atoms adsorbed at M form the most stable structure, followed by adsorption at H and then X. The increased distance between the Cu adatoms causes them to behave as independent single atoms, as can be seen from their lack of a metal-metal interaction energy, see table . This trend is also clear in the binding energy per atom of these Separated clusters, as the Neighbouring Colour scheme is identical to that in figure configurations are significantly more stable than Separated and single atom adsorption. There is no increase in binding energy for Separated structures when compared to the single atom adsorption. This further emphasises that metal-metal energies are a driving force in cluster stability. It should be noted that as Separated adsorption is equivalent to single atom adsorption due to an absence of inter-copper interaction, Separated adsorption at site X is not a stable adsorption at finite temperature. Similar to Cu 1 adsorption, Separated configurations are most stable on WTe 2 , then WS 2 and WSe 2 . However, on the WTe 2 monolayer there is no longer any difference in stability between atoms adsorbed at M and H.