Preparation and Structure Refinement of Monoclinic Hydroxyapatite

Toshiyuki Ikoma*, Atsushi Yamazaki, Satoshi Nakamura, Masaru Akao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

92 Citations (Scopus)


Monoclinic hydroxyapatite was synthesized by a wet method followed by heating in air at 1473 K for 1 h. The product is carbonate-free and has a Ca/P ratio of 1.65, which is slightly lower than the theoretical value (1.67) of hydroxyapatite. The crystal structure was investigated by Rietveld refinement using X-ray powder diffraction data. The structure has monoclinic symmetry with the space groupP21/b(No. 14),Z=4,Dx=3.14 g cm-3, and the lattice constants area=9.426(3) Å,b=18.856(5) Å,c=6.887(1) Å, andγ=119.97(1)°. The hydroxyl ions have an ordered arrangement along the hydroxyl columns. The hydroxyapatite prepared in the present study is 98% monoclinic.

Original languageEnglish
Pages (from-to)272-276
Number of pages5
JournalJournal of Solid State Chemistry
Issue number2
Publication statusPublished - 1999 May


  • Hydroxyapatite
  • Monoclinic phase
  • Rietveld refinement
  • Wet method
  • X-ray powder diffraction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


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