The Completion of the Platonic Atomic Polyhedra: The Dodecahedron

Binary AuPd nanoparticles in the 1–2 nm size range have been imaged by high-resolution electron microscopy (HREM). A dodecahedral atomic growth pattern is identified in the round-shaped particles (such a dodecahedron is shown as a ball model (left) and a simulated microscope image (right)), which make up 85 % of the total product. The results demonstrate the first experimental evidence of this Platonic form for metallic nanoparticles of this size. The stability of such structures has been validated through theoretical calculations.