data_global _chemical_name_mineral 'Fluorapatite' loop_ _publ_author_name 'Hughes J M' 'Cameron M' 'Crowley K D' _journal_name_full 'American Mineralogist' _journal_volume 76 _journal_year 1991 _journal_page_first 1857 _journal_page_last 1862 _publ_section_title ; Ordering of divalent cations in the apatite structure: Crystal structure refinements of natural Mn- and Sr-bearing apatite sample Sr.63 ; _database_code_amcsd 0001421 _chemical_formula_sum '(Ca4.686 Sr.314) P3 O12 F' _cell_length_a 9.3902 _cell_length_b 9.3902 _cell_length_c 6.9011 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 526.985 _exptl_crystal_density_diffrn 3.272 _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 _atom_site_U_iso_or_equiv Ca1 0.66667 0.33333 0.00086 0.98400 0.01077 Sr1 0.66667 0.33333 0.00086 0.01600 0.01077 Ca2 -0.00854 0.24046 0.25000 0.90600 0.01003 Sr2 -0.00854 0.24046 0.25000 0.09400 0.01003 P 0.36912 0.39843 0.25000 1.00000 0.00760 O1 0.48460 0.32690 0.25000 1.00000 0.01203 O2 0.46650 0.58770 0.25000 1.00000 0.01431 O3 0.25740 0.34160 0.07110 1.00000 0.01596 F 0.00000 0.00000 0.25000 1.00000 0.02533