data_global _chemical_name_mineral 'Enstatite' loop_ _publ_author_name 'Yang H' 'Ghose S' _journal_name_full 'American Mineralogist' _journal_volume 80 _journal_year 1995 _journal_page_first 9 _journal_page_last 20 _publ_section_title ; A transitional structural state and anomalous Fe-Mg order-disorder in Mg-rich orthopyroxene, (Mg0.75Fe0.25)2Si2O6 T = 1100 K ; _database_code_amcsd 0001695 _chemical_formula_sum '(Mg.751 Fe.249) Si O3' _cell_length_a 18.4105 _cell_length_b 8.9691 _cell_length_c 5.2540 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 867.570 _exptl_crystal_density_diffrn 3.315 _symmetry_space_group_name_H-M 'P b c a' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,1/2+z' '-x,1/2+y,1/2-z' '1/2-x,1/2+y,z' '1/2+x,1/2-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 Mg1 0.37510 0.65180 0.88260 0.90100 Fe1 0.37510 0.65180 0.88260 0.09900 Mg2 0.37670 0.48560 0.37840 0.60100 Fe2 0.37670 0.48560 0.37840 0.39900 SiA 0.27200 0.33970 0.06100 1.00000 SiB 0.47500 0.33760 0.78640 1.00000 O1A 0.18460 0.33940 0.05300 1.00000 O1B 0.56270 0.34050 0.78880 1.00000 O2A 0.31110 0.49760 0.06540 1.00000 O2B 0.43420 0.48530 0.70120 1.00000 O3A 0.30230 0.23200 -0.16750 1.00000 O3B 0.44890 0.20840 0.57800 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 0.02404 0.02201 0.01902 0.00000 -0.00392 0.00048 Fe1 0.02404 0.02201 0.01902 0.00000 -0.00392 0.00048 Mg2 0.03606 0.03016 0.02545 -0.00251 -0.00784 0.00167 Fe2 0.03606 0.03016 0.02545 -0.00251 -0.00784 0.00167 SiA 0.01545 0.01712 0.01398 -0.00251 0.00000 0.00000 SiB 0.01545 0.01752 0.01552 0.00000 -0.00196 0.00000 O1A 0.01717 0.02445 0.02293 0.00000 0.00049 -0.00143 O1B 0.01545 0.02894 0.02335 -0.00167 -0.00294 0.00191 O2A 0.03263 0.02364 0.02685 -0.01004 -0.00294 0.00215 O2B 0.02919 0.01997 0.02741 0.00920 -0.00049 0.00358 O3A 0.02576 0.03831 0.01916 -0.00167 0.00000 -0.01122 O3B 0.02576 0.03301 0.02489 -0.00251 0.00245 -0.01122