The structure of the lithium-rich garnets li6la2m2o12 and li6.4sr1.4la1.6m2o12 (m = sb, ta)

O'Callaghan, M.P. and Cussen, E.J. (2008) The structure of the lithium-rich garnets li6la2m2o12 and li6.4sr1.4la1.6m2o12 (m = sb, ta). Solid State Sciences, 10 (4). pp. 390-395. ISSN 1293-2558

[img] Microsoft Word
Revised_EJCussen_Li_rich_Garnets_text.doc
Accepted Author Manuscript

Download (94kB)
    [img]
    Preview
    Image (TIFF)
    EJCussen_Li_rich_Garnets_Fig_5.tif
    Preprint

    Download (1MB)| Preview
      [img]
      Preview
      Image (TIFF)
      EJCussen_Li_rich_Garnets_Fig_1.tif
      Preprint

      Download (3MB)| Preview
        [img]
        Preview
        Image (TIFF)
        EJCussen_Li_rich_Garnets_Fig_4.tif
        Preprint

        Download (1MB)| Preview
          [img] Microsoft Word
          EJCussen_Li_rich_Garnets_Table1.doc
          Preprint

          Download (56kB)
            [img]
            Preview
            Image (TIFF)
            EJCussen_Li_rich_Garnets_Fig_3.tif
            Preprint

            Download (1MB)| Preview
              [img] Microsoft Word
              EJCussen_Li_rich_Garnets_Table3_Revised.doc
              Preprint

              Download (64kB)
                [img]
                Preview
                Image (TIFF)
                EJCussen_Li_rich_Garnets_Fig_2.tif
                Preprint

                Download (1MB)| Preview
                  [img] Microsoft Word
                  EJCussen_Li_rich_Garnets_Table2.doc
                  Preprint

                  Download (41kB)

                    Abstract

                    Lithium garnets of the composition Li6SrLa2M2O12 and Li6.4Sr1.4La1.6M2O12 (M = Sb, Ta) have been prepared by solid state methods. Stuctural refinement against neutron powder diffraction data shows that these compounds crystallise in the space group Ia (3) over bard with lattice parameters in the range a = 12.85750(14) angstrom for Li6SrLa2Ta2O12 to 12.91371(13) angstrom for Li6.4Sr1.4La1.6Sb2O12. The observed increase in lattice parameter between M = Ta and Sb in both the Li6SrLa2M2O12 and Li6.4Sr1.4La1.6M2O12 compounds arises as a result of the different polarisabilities of these two cations. These phases contain a disordered arrangement of Sr2+/La3+ in eightfold coordination and Ta/Sb in fully-occupied oxide octahedra. All compounds contain lithium in a mixture of partially occupied tetrahedral and octahedral interstices with considerable positional disorder observed in the latter. Increasing the lithium stoichiometry causes a reduction in the occupation of the tetrahedrally-coordinated sites and a simultaneous increase in the concentration of lithium found within the oxide octahedra.