Characterization of the formation of magic-sized {Bi38O45} clusters by PDF and SAXS

Abstract

Bismuth oxido clusters exist in a range of sizes, all built up by octahedral {Bi6O8} units. While the atomic structure of various clusters has been solved by single crystal diffraction, it is much more challenging to study clusters directly in solution. Here, we use in situ X-ray total scattering with Pair Distribution Function (PDF) analysis to study the formation of the {Bi38O45}a cluster from [Bi6O5(OH)3(NO3)5]·(H2O)3 crystals dissolved in DMSO. The implementation of PDF analysis provides a unique insight into the structural rearrangements on the atomic scale. By combining with Small Angle X-ray Scattering (SAXS) we can furthermore investigate the size, morphology and size 10 dispersion of the clusters taking place in the process. Consequently, the combination of these two complementary techniques provides a mean of bridging the local atomic and macroscopic characteristics of the material.
In the presented study, the results obtained show that the reaction goes through several stable intermediates before the magic-sized product {Bi38O45} is reached. Through an associated temperature study, the intermediate was furthermore found to be capable of stabilization of up to days by varying the resulting reaction rate. The present studies show how powerful a tool the Debye Equation is in combination with 15 SAXS and PDF, which in this field is a new development that has a large potential for unravelling important questions in nanochemistry in solution.