کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1332626 | 979048 | 2007 | 8 صفحه PDF | دانلود رایگان |
The garnets Li3Nd3W2O12 and Li5La3Sb2O12 have been prepared by heating the component oxides and hydroxides in air at temperatures up to 950 °C. Neutron powder diffraction has been used to examine the lithium distribution in these phases. Both compounds crystallise in the space group Ia3¯d with lattice parameters a=12.46869(9) Å (Li3Nd3W2O12) and a=12.8518(3) Å (Li5La3Sb2O12). Li3Nd3W2O12 contains lithium on a filled, tetrahedrally coordinated 24d site that is occupied in the conventional garnet structure. Li5La3Sb2O12 contains partial occupation of lithium over two crystallographic sites. The conventional tetrahedrally coordinated 24d site is 79.3(8)% occupied. The remaining lithium is found in oxide octahedra which are linked via a shared face to the tetrahedron. This lithium shows positional disorder and is split over two positions within the octahedron and occupies 43.6(4)% of the octahedra. Comparison of these compounds with related d0 and d10 phases shows that replacement of a d0 cation with d10 cation of the same charge leads to an increase in the lattice parameter due to polarisation effects.
Li3Nd3W2O12 contains lithium on a filled tetrahedrally coordinated site. The Li-rich phase Li5La3Sb2O12 accommodates lithium on a mixture of tetrahedrally and octahedrally coordinated sites linked by a shared oxide face. The d0 garnets show substantially contracted unit cells compared to d10 analogues.Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 180, Issue 6, June 2007, Pages 1832–1839