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Pan, Y. and Fleet, M.E. (2002) Compositions of the Apatite-Group Minerals: Substitution Mechanisms and Controlling Factors. In: Kohn, M.J., Rakovan, J. and Hughes, J.M., Eds., Phosphates: Geochemical, Geobiological and Material Importance, Reviews in Mineralogy and Geochemistry, Vol. 48, Mineralogical Society of America, Washington DC, 13-50.
https://doi.org/10.2138/rmg.2002.48.2

has been cited by the following article:

• TITLE: Lanthanum-Neodymium-Co-Substituted Calcium Fluorobritholites

  AUTHORS: Mustapha Hidouri, Nawaf Albeladi

  KEYWORDS: Calcium Fluorobritholites, Lanthanum-Neodymium, Ionic Substitutions

  JOURNAL NAME: Journal of Materials Science and Chemical Engineering, Vol.6 No.7, July 31, 2018

  ABSTRACT: Britholites are considered as potential matrices for storage of nuclear wastes such as minor actinides and long-lived fission byproducts. This investigation is concerned with the study of simultaneous substitution in calcium fluor-britholite framework of two lanthanide ions assimilated to radionuclides. A series of calcium fluorbritholites doped with lanthanum and neodymium Ca8La2-xNdx(PO4)4(SiO4)2F2 with 0 ≤ x ≤ 2 were prepared via a solid state reaction in the temperature range 1450℃- 1250℃. The obtained products were characterized by several techniques such as Chemical analysis via Inductively coupled plasma Atomic emission spectrometry ICP-AES, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy FTIR and Nuclear magnetic resonance 31P NMR (MAS). Obtained solid solutions containing lanthanum and neodymium in variable proportions were typically apatite of hexagonal structure P63/m spatial group. The stoichiometry of the powders was verified via the metal/(phosphate + silicate) molar ratios found at about 1.67. The lattice parameters a and c calculated by the Rietveld method decreased as neodymium level increased. Despite, the close respective sizes of lanthanum and neodymium ions (VIrLa3+= 1.032A, VIrNd3+= 0.983A), their mutual substitutions led to solid solutions in whole range of composition with preferential occupation of Me (2) sites.