Title of article :
Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca2RE8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2
Author/Authors :
Crum, Jarrod V. Pacific Northwest National Laboratory, USA , Chong, Saehwa Pacific Northwest National Laboratory, USA , Peterson, Jacob A. Pacific Northwest National Laboratory, USA , Riley, Brian J. Pacific Northwest National Laboratory, USA
Abstract :
Six different rare-earth oxyapatites, including Ca2RE8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2, were synthesized using solution-based processes followed by cold pressing and sintering. The crystal structures of the synthesized oxyapatites were determined from powder X-ray diffraction (P-XRD) and their chemistries verified with electron probe microanalysis (EPMA). All the oxyapatites were isostructural within the hexagonal space group P63/m and showed similar unit-cell parameters. The isolated [SiO4]4− tetrahedra in each crystal are linked by the cations at the 4f and 6h sites occupied by RE3+ and Ca2+ in Ca2RE8(SiO4)6O2 or La3+ and Na+ in NaLa9(SiO4)6O2. The lattice parameters, cell volumes, and densities of the synthesized oxyapatites fit well to the trendlines calculated from literature values.
Keywords :
oxyapatite , lanthanide oxyapatite , rare-earth oxyapatite , powder diffraction
Journal title :
Acta Crystallographica Section E: Crystallographic Communications
