Second-sphere complexes in analytical chemistry

Literary data on the application in the modern analytical chemistry of outer-sphere complexes, forming from coordination-saturated inner-sphere complexes and ligands, cation particles or organic solvent molecules in the second sphere are summarised. It is shown, that the outer-sphere complexes peculiarities, involving in their relatively low stability and activation energy for the processes in the second sphere, together with their variety allows one to effectively use these complexes for separation, extraction and, especially, determination of inorganic and organic substances. Outer-sphere complexes are used to determine some transition metals, lanthanides, berillium, boron and some other elements. The improvement of sensitivity, selectivity and expressiveness of analytical determination, achieved here, is discussed