New data on the crystal structures of natural zirconosilicates: structure refinements and ion-exchange behavior

A review of the mineralogical, structural and crystal-chemical studies carried out on a large group of natural zirconosilicates is reported. These zirconosilicates belong to a large number of distinct structural types, and those with mixed frameworks of isolated Zr-centred octahedra and silicate complexes are described according to the degree of condensation of SiO 4 tetrahedra.The microporous heteropolyhedral nature of these phases is considered in connection with their ion exchange properties. The application of X-ray diffractometers equipped with CCD detectors, use of the Rietveld method, and electron microprobe and IR spectroscopic data provide new insights into the structural peculiarities of these minerals. The results stimulate the search for new Zr—Si-compounds with potential applications in the areas of catalysis, separation of molecules, ion exchange, etc.