title: Structure and ion exchange properties of a new cobalt borate with a tunnel structure "templated" by Na+.
abstract: The new anhydrous borate Na2Co2B12O21 has been synthesized by flux methods and studied by single-crystal X-ray diffraction (space group I2/a with a = 17.1447(15) A, b = 4.5530(5) A, c = 19.4408(15) A, beta = 103.212(5) degrees , V = 1477.4(2) A3, Z = 4). Refinement of its structure reveals it is the first metaborate exhibiting a tunnel network, with internal dimensions of 4.5 x 8.8 A2. Further single-crystal diffraction studies show that the Na+ ions within the tunnels are exchangeable with Li+ along with the absorption of water molecules to form Li2(H2O)2Co2B12O21, making this compound a unique non-siliceous zeotype.
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Jesse L C
authors.initials: JL
authors.lastname: Rowsell
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Taylor
authors.forename: Linda F
authors.initials: LF
authors.lastname: Nazar