Cation—cation interaction in crystalline actinide compounds

The published data on the structures and properties of crystalline actinide compounds having mutually coordinated AnO₂⁺ or AnO₂ ²⁺ cations as structural elements are surveyed. This cation—cation interaction is an important structure-forming factor for many crystalline compounds of Np(V) and U(VI). It strongly affects their UV-Vis and IR spectra as well as other properties. Differences and similarities between the cation—cation interactions of actinide ions in solutions and crystals are discussed.