Fig. 1From: Facile Synthesis of Ligand-Free Iridium Nanoparticles and Their In Vitro Biocompatibilitya Iridium nanoparticles are 2–3 nm by TEM imaging, with b with a highly crystalline lattice parameter. c XRD spectrum matches elemental iridium, and d particles have a hydrodynamic size of 5 nm in water by DLSBack to article page