Structural Diversity of Dimer Clusters Based on the Octadecahydro-Eicosaborate Anion

The work summarizes the data on currently known dimeric boron cluster anions with the general formula [B20H18](2-). Their preparation, structure, and the methods of structural modification are considered. The data on the reactivity of boron dimeric clusters in redox, substitution, complexation, and condensation reactions are presented. The isomerism of dimeric polyhedral boron cluster anions associated with the formation of substituted derivatives and coordination compounds is considered. The methods of reversible transformation of isomers in salts and coordination compounds in solutions and single crystals are discussed.