data_global _chemical_name_mineral 'Carbonate-fluorapatite' loop_ _publ_author_name 'Perdikatsis B' _journal_name_full 'Materials Science Forum' _journal_volume 79 _journal_year 1991 _journal_page_first 809 _journal_page_last 814 _publ_section_title ; X-ray powder diffraction study of francolite by the Rietveld method Sample: T = 750 C Note: Reported structure does not reproduce reported formula or bondlengths ; _database_code_amcsd 0014387 _chemical_compound_source 'Epirus, Greece' _chemical_formula_sum 'Ca2.108 P1.362 O8.817 F.171' _cell_length_a 9.3593 _cell_length_b 9.3593 _cell_length_c 6.8919 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 522.825 _exptl_crystal_density_diffrn 1.721 _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 0.33333 0.66667 0.00020 0.32800 0.01335 Ca2 0.24140 0.99140 0.25000 0.48400 0.01035 P 0.39830 0.36890 0.25000 0.45400 0.01232 O1 0.32550 0.48380 0.25000 0.45100 0.00583 O2 0.58700 0.46260 0.25000 0.48800 0.02058 O3 0.34200 0.25650 0.06790 1.00000 0.02088 F 0.00000 0.00000 0.25000 0.17100 0.05181