Different samples of fine metal colloids synthesized following an organometallic route were investigated by High Resolution Transmission Electron Microscopy (HREM) and Wide Angle X-rays Scattering (WAXS). Simulations based on models for crystalline and multiply twinned particles were used to interpret the observations. Deviations from the bulk structure were clearly observed in the smaller particles and attributed to an effect of dimensions. Combined HREM and WAXS experiments proved to be very efficient in the study of ultrafine particles. In particular, 55-atoms fcc Pt particles were identified.
