Sols were prepared by mixing solutions of bismuth nitrate and thiourea in
N,
N-dimetilformamide. Thecorresponding colloidal particles were characterized by using X-ray powder diffraction, scanning andtransmission electron microscopy, and quasielastic light scattering. Two size distributions of colloidal particleswere found: one at 5 nm and another at 300 nm. The small colloidal particles were nanocapsules that aggregatedto produce larger nanocapsules with diameters between 10 and 40 nm and a shell thickness of 5 nm, whichaggregated to produce the large colloidal particles with the diameter of 300 nm. The capsule shells werenoncrystalline, made of Bi-S atomic clusters that contained two bismuth and five sulfur atoms; the clustersformed chains and double Bi-S layers linked via metallic Bi-Bi bonds. Increasing the bismuth concentrationin the sol induced the crystallization of the sample into the crystalline structure of bismuthinite. Aging the solat different temperatures caused aggregation of the large nanocapsules into one-dimensional arrays that alsointeracted with each other, forming broccoli-like objects with dimensions of some micrometers. Aging thesol at 80
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C gave rise to a dendritic crystallization of bismuthinite.