data_global _chemical_name_mineral 'Cummingtonite' loop_ _publ_author_name 'Yang H' 'Smyth J R' _journal_name_full 'American Mineralogist' _journal_volume 81 _journal_year 1996 _journal_page_first 363 _journal_page_last 368 _publ_section_title ; Crystal structure of a P2_1/m ferromagnesian cummingtonite at 140 K T = 140 K ; _database_code_amcsd 0001788 _chemical_formula_sum '(Mg4.441 Fe2.559) Si8 O24' _cell_length_a 9.492 _cell_length_b 18.093 _cell_length_c 5.292 _cell_angle_alpha 90 _cell_angle_beta 102.11 _cell_angle_gamma 90 _cell_volume 888.617 _exptl_crystal_density_diffrn 3.212 _symmetry_space_group_name_H-M 'P 1 21/m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,z' '-x,1/2+y,-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Mg1 -0.24960 0.33690 0.48880 0.80000 Fe1 -0.24960 0.33690 0.48880 0.20000 Mg2 -0.25030 0.42700 0.98860 0.91100 Fe2 -0.25030 0.42700 0.98860 0.08900 Mg3 -0.24910 0.25000 0.99050 0.83100 Fe3 -0.24910 0.25000 0.99050 0.16900 Mg4 -0.25220 0.50940 0.48480 0.09400 Fe4 -0.25220 0.50940 0.48480 0.90600 Si1a 0.03850 0.33460 0.26260 1.00000 Si1b 0.53780 0.83350 0.28740 1.00000 Si2a 0.04600 0.42000 0.76880 1.00000 Si2b 0.54940 0.91750 0.79370 1.00000 O1a -0.13520 0.33680 0.19920 1.00000 O1b 0.36470 0.83740 0.21940 1.00000 O2a -0.12800 0.42220 0.70570 1.00000 O2b 0.37500 0.92230 0.73160 1.00000 O3a -0.13360 0.25000 0.69860 1.00000 O3b 0.36130 0.75000 0.71710 1.00000 O4a 0.12800 0.49770 0.78110 1.00000 O4b 0.63290 0.99290 0.76130 1.00000 O5a 0.10100 0.37330 0.03410 1.00000 O5b 0.60320 0.88710 0.09050 1.00000 O6a 0.10350 0.37830 0.53130 1.00000 O6b 0.59740 0.86050 0.58270 1.00000 O7a 0.09480 0.25000 0.29170 1.00000 O7b 0.59250 0.75000 0.25790 1.00000 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 Mg1 0.00567 0.00332 0.00298 -0.00085 0.00122 0.00047 Fe1 0.00567 0.00332 0.00298 -0.00085 0.00122 0.00047 Mg2 0.00611 0.00498 0.00298 -0.00085 0.00049 0.00000 Fe2 0.00611 0.00498 0.00298 -0.00085 0.00049 0.00000 Mg3 0.00567 0.00498 0.00326 0.00000 0.00049 0.00000 Fe3 0.00567 0.00498 0.00326 0.00000 0.00049 0.00000 Mg4 0.00611 0.00663 0.00203 0.00000 0.00146 0.00000 Fe4 0.00611 0.00663 0.00203 0.00000 0.00146 0.00000 Si1a 0.00349 0.00332 0.00271 0.00000 -0.00024 0.00000 Si1b 0.00611 0.00332 0.00231 -0.00085 0.00097 0.00000 Si2a 0.00567 0.00332 0.00285 -0.00085 0.00024 0.00000 Si2b 0.00349 0.00498 0.00203 -0.00085 -0.00073 0.00047 O1a 0.00349 0.00663 0.00258 0.00000 0.00049 -0.00095 O1b 0.00829 0.00166 0.00597 0.00085 0.00122 0.00190 O2a 0.00611 0.00498 0.00637 -0.00170 0.00243 0.00000 O2b 0.00393 0.00498 0.00583 0.00085 0.00049 0.00190 O3a 0.01047 0.00663 0.00475 0.00000 0.00243 0.00000 O3b 0.00655 0.00332 0.00488 0.00000 0.00024 0.00000 O4a 0.00436 0.00332 0.00637 -0.00170 -0.00122 0.00142 O4b 0.01091 0.00995 0.00502 -0.00255 0.00219 -0.00190 O5a 0.00567 0.00829 0.00488 -0.00085 0.00073 0.00474 O5b 0.00698 0.00498 0.00339 0.00085 0.00024 0.00095 O6a 0.00655 0.00995 0.00529 0.00170 -0.00122 -0.00190 O6b 0.00480 0.00995 0.00393 0.00170 -0.00049 -0.00142 O7a 0.00916 0.00829 0.00434 0.00000 -0.00049 0.00000 O7b 0.00524 0.00332 0.00787 0.00000 0.00389 0.00000