data_global _chemical_name_mineral 'Hydroxylapatite' loop_ _publ_author_name 'Wilson R M' 'Elliot J C' 'Dowker S E P' _journal_name_full 'American Mineralogist' _journal_volume 84 _journal_year 1999 _journal_page_first 1406 _journal_page_last 1414 _publ_section_title ; Rietveld refinement of the crystallographic structure of human dental enamel apatites Sample: RGP - enamel ; _database_code_amcsd 0002292 _chemical_formula_sum 'Ca4.76 Na.1 Mg.02 P2.82 O12.25 H1.62' _cell_length_a 9.4554 _cell_length_b 9.4554 _cell_length_c 6.8835 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 532.966 _exptl_crystal_density_diffrn 2.982 _symmetry_space_group_name_H-M 'P 63/m' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x+y,-x,1/2-z' 'x-y,x,1/2+z' 'y,-x+y,-z' '-y,x-y,z' 'x,y,1/2-z' '-x,-y,1/2+z' 'x-y,x,-z' '-x+y,-x,z' '-y,x-y,1/2-z' 'y,-x+y,1/2+z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Ca1 0.66667 0.33333 0.00260 0.97000 Na1 0.66667 0.33333 0.00260 0.02000 Mg1 0.66667 0.33333 0.00260 0.01000 Ca2 0.24710 0.99090 0.25000 0.94000 Na2 0.24710 0.99090 0.25000 0.02000 P 0.39960 0.36920 0.25000 0.94000 O1 0.33110 0.48570 0.25000 0.93000 O2 0.58050 0.45990 0.25000 0.98000 O3 0.34080 0.25770 0.07180 0.91000 O-h 0.00000 0.00000 0.18180 0.53000 H 0.00000 0.00000 0.06080 0.81000