Abstract
Two new solubility-limiting phases relevant to nuclear waste disposal are reported, namely CeSiO4 and Ca2Ce8(SiO4)O-2, produced by hydrothermal synthesis at 180 degreesC. X-ray diffraction data are presented for both compounds. Rietveld refinement was performed for each of these phases. CeSiO4 was confirmed to be a zircon structure type, with space group 14(1)/amd, unit cell a=6.9564(3), c= 6.1953(4) Angstrom. Bond lengths for SiO4 are in excellent agreement with published values; Ce4+ is coordinated to eight oxygen atoms with four regular and four short bonds. Ca2Ce8(SiO4)O-2 was shown to have an apatite structure, with space group P6(3)/m and unit cell a=9.4343(3), c = 6.8885(4) Angstrom. The unit cell and bond lengths were found to be slightly smaller than would be expected from other lanthanide-containing analogs; possible reasons for this are discussed. (C) 2000 International Centre for Diffraction Data. [S0885-7156(00)00103-2].
| Original language | English |
|---|---|
| Pages (from-to) | 234-238 |
| Number of pages | 5 |
| Journal | Powder Diffraction |
| Volume | 15 |
| Publication status | Published - 2000 |
Keywords
- Rietveld refinement
- powder diffraction
- actinide simulants
- cement nuclear waste disposal
- NEUTRON POWDER DIFFRACTION
- BOND LENGTHS
- ZIRCON