The coincidence lattice formed between a crystalline MgO film and a Mo(001) support is found to be an ideal template to produce long-range ordered ensembles of Fe and Cr particles for electronic, magnetic and chemical applications. The structural and electronic properties of this super-lattice are analyzed by means of scanning tunnelling microscopy and density functional theory. The different registers of atoms at the interface induce periodic changes in the MgO lattice parameter, in the metal-oxide binding length, and the workfunction. These variations modulate the adsorption landscape for Cr and Fe atoms and give rise to the observed ordering phenomena. Preferred nucleation and growth is revealed in those regions of the coincidence lattice that have a small lattice mismatch with the ad-particles and enable electron-transfer processes with the support.