data_global _chemical_name_mineral 'Omphacite' loop_ _publ_author_name 'Matsumoto T' 'Tokonami M' 'Morimoto N' _journal_name_full 'American Mineralogist' _journal_volume 60 _journal_year 1975 _journal_page_first 634 _journal_page_last 641 _publ_section_title ; The crystal structure of omphacite ; _database_code_amcsd 0000466 _chemical_formula_sum 'Si4 Al.868 Fe.317 Mg.815 (Ca1.03 Na.97) O12' _cell_length_a 9.585 _cell_length_b 8.776 _cell_length_c 5.260 _cell_angle_alpha 90 _cell_angle_beta 106.8 _cell_angle_gamma 90 _cell_volume 423.576 _exptl_crystal_density_diffrn 3.362 _symmetry_space_group_name_H-M 'P 1 2/n 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2-x,y,1/2-z' '1/2+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 Si1 0.53930 0.34650 0.22730 1.00000 0.00469 Si2 0.53760 0.16210 0.73100 1.00000 0.00456 Al1 0.25000 0.34800 0.75000 0.86800 0.00405 Fe1 0.25000 0.34800 0.75000 0.13200 0.00405 Mg2 0.25000 0.15800 0.25000 0.81500 0.00545 Fe2 0.25000 0.15800 0.25000 0.18500 0.00545 Ca3 0.25000 0.55210 0.25000 0.31400 0.01089 Na3 0.25000 0.55210 0.25000 0.68600 0.01089 Ca4 0.25000 0.95020 0.75000 0.71600 0.01039 Na4 0.25000 0.95020 0.75000 0.28400 0.01039 O1 0.36340 0.33820 0.12320 1.00000 0.00925 O2 0.36210 0.17670 0.64750 1.00000 0.00937 O3 0.61380 0.50900 0.30910 1.00000 0.00963 O4 0.60630 0.99740 0.80540 1.00000 0.01013 O5 0.60570 0.26630 0.00370 1.00000 0.00823 O6 0.59810 0.23980 0.49840 1.00000 0.00887