data_global _chemical_name_mineral 'Pigeonite' loop_ _publ_author_name 'Morimoto N' 'Guven N' _journal_name_full 'American Mineralogist' _journal_volume 55 _journal_year 1970 _journal_page_first 1195 _journal_page_last 1209 _publ_section_title ; Refinement of the crystal structure of pigeonite ; _database_code_amcsd 209 _chemical_compound_source 'Isle of Mull, Scotland' _chemical_formula_sum 'Mg.78 Fe1.04 Ca.18 Si2 O6' _cell_length_a 9.706 _cell_length_b 8.95 _cell_length_c 5.246 _cell_angle_alpha 90.0 _cell_angle_beta 108.59 _cell_angle_gamma 90.0 _cell_volume 431.936 _exptl_crystal_density_diffrn 3.636 _symmetry_space_group_name_H-M 'P 1 21/c 1' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,1/2+z' '-x,1/2+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 Mg1 0.2508 0.6548 0.2328 0.72 Fe1 0.2508 0.6548 0.2328 0.28 Fe2 0.2564 0.0183 0.2308 0.76 Ca2 0.2564 0.0183 0.2308 0.18 Mg2 0.2564 0.0183 0.2308 0.06 SiA 0.0427 0.3398 0.2797 1.0 SiB 0.5504 0.8367 0.2372 1.0 O1A 0.8659 0.3404 0.1715 1.0 O2A 0.122 0.497 0.3306 1.0 O3A 0.1037 0.2633 0.5779 1.0 O1B 0.3743 0.8342 0.1344 1.0 O2B 0.629 0.9877 0.3765 1.0 O3B 0.6053 0.7087 0.4773 1.0 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 0.00729 0.00649 0.00977 0.00042 0.00301 0.00023 Fe1 0.00729 0.00649 0.00977 0.00042 0.00301 0.00023 Fe2 0.01201 0.01826 0.01428 0.00209 0.00162 0.00113 Ca2 0.01201 0.01826 0.01428 0.00209 0.00162 0.00113 Mg2 0.01201 0.01826 0.01428 0.00209 0.00162 0.00113 SiA 0.00729 0.00609 0.00864 -0.00042 0.00232 -0.00271 SiB 0.006 0.00649 0.00651 -0.00167 0.00185 0.00135 O1A 0.00472 0.00933 0.00839 -0.00167 0.0007 -0.00293 O2A 0.01758 0.00528 0.00952 -0.00083 0.00742 -0.0018 O3A 0.006 0.01217 0.01516 -0.0025 0.00185 0.00519 O1B 0.00986 0.00649 0.00701 0.00125 0.00394 -0.00158 O2B 0.00943 0.01826 0.01741 -0.00751 0.00765 -0.00744 O3B 0.00429 0.01542 0.01328 -0.00209 0.0007 0.00541