Novel synthetic alkali-yttrium silicates with a new microporous mixed framework topology: (Rb,CS)(9)Y7Si24O63 and isotypic Rb9Y7Si24O63

摘要

Prismatic colourless crystals of the two novel, isotypic title compounds were obtained by the flux growth technique. The crystal structures have been determined from single-crystal intensity data in space group R (3) over bar with a = 28.819(4) / 28.799(4), c = 13.916(3) / 13.864(3) angstrom, V = 10009(3) / 9958(3) angstrom(3) Z = 6, R(F) = 4.99 / 6.44 %, respectively. They represent a novel structure type with microporous character. The framework is built from six-membered silicate rings (approximate UDUDUD orientation) containing isolated YO6 octahedra and compressed "six-membered rings", which in fact build a spiral of corner-sharing SiO4 tetrahedra. Approximately parallel to [111] run two different irregular channels hosting the Rb/Cs and Rb atoms.