data_global _chemical_name_mineral 'Cordierite' loop_ _publ_author_name 'Koepke J' 'Schulz H' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 13 _journal_year 1986 _journal_page_first 165 _journal_page_last 173 _publ_section_title ; Single crystal structure investigations under high-pressure of the mineral cordierite with an improved high-pressure cell Sample: P = 1.2 GPa ; _database_code_amcsd 0007386 _chemical_compound_source 'Zabargad island, Red Sea' _chemical_formula_sum 'Mg2 Al4 Si5 O18' _cell_length_a 17.013 _cell_length_b 9.680 _cell_length_c 9.3035 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 1532.155 _exptl_crystal_density_diffrn 2.536 _symmetry_space_group_name_H-M 'C c c m' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' 'x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '-x,y,1/2-z' '1/2-x,1/2+y,1/2-z' '-x,y,1/2+z' '1/2-x,1/2+y,1/2+z' 'x,-y,1/2-z' '1/2+x,1/2-y,1/2-z' 'x,y,-z' '1/2+x,1/2+y,-z' '-x,-y,z' '1/2-x,1/2-y,z' '-x,-y,-z' '1/2-x,1/2-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Mg 0.16220 0.50000 0.25000 0.00690 Al11 0.25000 0.25000 0.25030 0.00720 Si16 0.00000 0.50000 0.25000 0.00610 Si21 0.19300 0.07790 0.00000 0.00420 Al26 0.05060 0.30830 0.00000 0.00510 Si23 -0.13510 0.23740 0.00000 0.00570 O11 0.24740 0.10310 0.14210 0.00680 O16 0.06240 0.41540 0.15060 0.00780 O13 -0.17330 0.31160 0.14230 0.00780 O21 0.12280 0.18510 0.00000 0.01120 O26 -0.04280 0.24800 0.00000 0.00820 O23 -0.16470 0.08060 0.00000 0.01060