STRUCTURES OF COMPLEXES IN SOLUTION DERIVED FROM X-RAY-DIFFRACTION MEASUREMENTS

This chapter presents a study on the structures of complexes in solution measurements derived from X-ray diffraction. The chapter presents a survey on the structures of the complexes derived from solution diffraction data. The methods used and the approximations involved are discussed in this chapter. Structure determinations of aqua complexes of metal ions in aqueous solutions are discussed only when they are of interest for the structures of complexes containing other ligands. A commonly used instrument for measuring the large-angle X-ray scattering from a solution is the ϴ-ϴ goniometer. The Bragg–Brentano parafocusing geometry is used in which the incoming X-ray beam and the measured diffracted beam form the same angle, ϴ, with the horizontal surface of the liquid sample. X-ray diffraction measurements can give direct structural information on complexes in solution that cannot be obtained by other methods. Comparison of diffraction curves for different solutions can give information on structural changes caused by the changes in concentration of a particular atomic species. for a dominant complex in a solution, precise determinations of the intramolecular distances can usually be made. Derivations of coordination numbers and geometries will depend on the specific characteristics of the system investigated. © 1992 Academic Press, Inc.