Dodecanethiol-stabilized gold nanoparticles with similar average size organize into different superlattice structures depending upon the method of preparation of the nanocrystals. Particles synthesized by the inverse micelle technique preferentially assemble into face-centered cubic (fcc) structures with long-range translational and orientational ordering. Gold nanoparticles obtained by the solvated metal atom dispersion (SMAD) method behave like "hard" spheres and predominantly organize into hexagonal close-packed (hcp) nanocrystal superlattices with long-range translational ordering. Different packing behavior results from differences in nanoparticle core morphologies induced by the synthetic method; fcc ordering is preferred by single crystalline nanoparticles, while hcp is preferred by polycrystalline nanoparticles. A combination of optical microscopy, transmission electron microscopy (TEM and HRTEM), selected area electron diffraction (SAED), atomic force microscopy (AFM), and X-ray diffraction (XRD) were used to characterize both the dispersed nanoparticles and the nanocrystal superlattices.

Oxidation of TiO or Ti2O3 led to the formation of TiO2 with activity in visible light much higher than when TiN was used as a precursor, pointing out the importance of oxygen defects/vacancies for extension of activity of TiO2 into the visible region.

Solid solutions of the formula, A,-,La,Ti3~,Nb,0,0 (A= K, Rb), exist for the range O

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