Water-in-oil reverse micelles of butyl ammonium laurate in hexanes that contain sodium hexachlororhodate were reduced with sodium borohydride to yield rhodium nanoparticles. The size of the micelle, determined by dynamic light scattering, was from 3 to 20 nm and varied as the water to surfactant ratio (W) was changed. The rhodium nanoparticles exhibited a Gaussian size distribution (sigma = 0.35 nm), with average diameters of 1.5, 2.2, and 2.9 nm. The products were characterized with TEM, HRTEM, and X-ray photoemission spectroscopy. (c) 2007 Elsevier Inc. All rights reserved.