Figure 1: Schematic display of the prolate cluster growth to a quasi spherical structure for the predicted ground state structures (GM) for SnN with N = 20; 25; 30 and 40 at the PBE0/def2-TZVPP level of theory. Tin atoms are displayed as gray spheres and the two building blocks are highlighted in red (double-capped square antiprism) and yellow (triple-capped trigonal prism).