data_global _chemical_name_mineral 'Pertsevite-(F)' loop_ _publ_author_name 'Brovkin A A' 'Nikishova L V' _journal_name_full 'Soviet Physics Crystallography' _journal_volume 20 _journal_year 1975 _journal_page_first 452 _journal_page_last 455 _publ_section_title ; The crystal structure of a-Mg2BO3F and the isomorphic substitution (3F)=(BO3) ; _database_code_amcsd 0015570 _chemical_compound_source 'Synthetic' _chemical_formula_sum 'Mg8 B4.56 O13.68 F2.32' _cell_length_a 20.44 _cell_length_b 4.530 _cell_length_c 11.80 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 1092.600 _exptl_crystal_density_diffrn 3.080 _symmetry_space_group_name_H-M 'P n a 21' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2-y,z' '1/2-x,1/2+y,1/2+z' '-x,-y,1/2+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 Mg1 0.01490 0.50400 0.02350 1.00000 0.00633 Mg2 0.48590 0.97400 0.26990 1.00000 0.00760 Mg3 0.24530 0.46800 0.25910 1.00000 0.00380 Mg4 0.25420 0.95600 0.03190 1.00000 0.00380 Mg5 0.12760 0.97400 0.16570 1.00000 0.00760 Mg6 0.11570 0.48200 0.39890 1.00000 0.00760 Mg7 0.38120 0.48600 0.12010 1.00000 0.00633 Mg8 0.37800 0.47200 0.39300 1.00000 0.00253 B1 0.34400 0.92400 0.23300 1.00000 0.00380 B2 0.18300 0.92700 0.39400 1.00000 0.00380 B3 0.15700 0.44500 0.06100 1.00000 0.00127 B4 0.02300 0.03200 0.42800 1.00000 0.00253 B5 0.02400 0.07000 0.19300 0.56000 0.00380 O1 0.03890 0.74300 0.15600 0.56000 0.00633 F1 0.03890 0.74300 0.15600 0.44000 0.00633 O2 0.02950 0.74700 0.39500 1.00000 0.00760 O3 0.10150 0.28000 0.02700 1.00000 0.01140 O4 0.06650 0.20000 0.49200 1.00000 0.00633 O5 0.16650 0.73200 0.03000 1.00000 0.00380 O6 0.17030 0.78200 0.49400 1.00000 0.00253 O7 0.19860 0.28900 0.12500 1.00000 0.00507 O8 0.20020 0.21500 0.39000 1.00000 0.00127 O9 0.30060 0.77300 0.16100 1.00000 0.00253 O10 0.46630 0.26900 0.14200 0.56000 0.00507 F10 0.46630 0.26900 0.14200 0.44000 0.00507 O11 0.46690 0.30300 0.39100 1.00000 0.00253 O12 0.17040 0.75800 0.29700 1.00000 0.00633 O13 0.33660 0.22200 0.25300 1.00000 0.00380 O14 0.07220 0.25400 0.26300 0.56000 0.01013 F14 0.07220 0.25400 0.26300 0.44000 0.01013 O15 0.39890 0.78800 0.26500 1.00000 0.00127 F 0.28890 0.64400 0.39500 1.00000 0.00380