data_global _chemical_name_mineral 'Phase-B-anhydrous' loop_ _publ_author_name 'Hazen R M' 'Finger L W' 'Ko J' _journal_name_full 'American Mineralogist' _journal_volume 77 _journal_year 1992 _journal_page_first 217 _journal_page_last 220 _publ_section_title ; Crystal chemistry of Fe-bearing anhydrous phase B: Implications for transition zone mineralogy ; _database_code_amcsd 0001445 _chemical_formula_sum 'Si5 Mg12.364 Fe1.616 O24' _cell_length_a 5.908 _cell_length_b 14.241 _cell_length_c 10.069 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 847.164 _exptl_crystal_density_diffrn 3.588 _symmetry_space_group_name_H-M 'P m c b' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2+y,1/2-z' '-x,1/2-y,1/2+z' 'x,1/2-y,1/2+z' '-x,1/2+y,1/2-z' '-x,y,z' 'x,-y,-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 Si1 0.00000 0.00000 0.00000 1.00000 0.00507 Si2 0.50000 0.31170 0.17584 1.00000 0.00507 Si3 0.00000 0.37466 0.99769 1.00000 0.00456 Mg1 0.50000 0.00000 0.50000 0.88100 0.00785 Fe1 0.50000 0.00000 0.50000 0.11900 0.00785 Mg2 0.50000 0.17325 0.35657 0.91000 0.00798 Fe2 0.50000 0.17325 0.35657 0.08000 0.00798 Mg3 0.50000 0.00000 0.00000 0.59100 0.00671 Fe3 0.50000 0.00000 0.00000 0.40900 0.00671 Mg4 0.24024 0.00208 0.25556 0.92500 0.00646 Fe4 0.24024 0.00208 0.25556 0.07500 0.00646 Mg5 0.00000 0.17678 0.82023 0.91200 0.00659 Fe5 0.00000 0.17678 0.82023 0.08800 0.00659 Mg6 0.24384 0.16952 0.08159 0.88700 0.00633 Fe6 0.24384 0.16952 0.08159 0.11300 0.00633 O1 0.00000 0.91360 0.34710 1.00000 0.00583 O2 0.00000 0.57520 0.35410 1.00000 0.00633 O3 0.00000 0.24190 0.49600 1.00000 0.00646 O4 0.50000 0.08630 0.17380 1.00000 0.00684 O5 0.50000 0.42480 0.17000 1.00000 0.00621 O6 0.50000 0.76050 0.47060 1.00000 0.00709 O7 0.23230 0.08810 0.42070 1.00000 0.00798 O8 0.21210 0.42670 0.42530 1.00000 0.00595 O9 0.28340 0.76220 0.25210 1.00000 0.00633