data_global _chemical_name_mineral 'Enstatite' loop_ _publ_author_name 'Hugh-Jones D A' 'Chopelas A' 'Angel R J' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 24 _journal_year 1997 _journal_page_first 301 _journal_page_last 310 _publ_section_title ; Tetrahedral compression in (Mg,Fe)SiO3 orthopyroxenes Sample: P = 3.00 GPa, natural orthopyroxene ; _database_code_amcsd 0008021 _chemical_formula_sum 'Mg1.66 Fe.24 Ca.012 Al.14 Si1.94 O6' _cell_length_a 18.115 _cell_length_b 8.7184 _cell_length_c 5.1472 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 812.917 _exptl_crystal_density_diffrn 3.407 _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 _atom_site_U_iso_or_equiv MgM1 0.37400 0.65410 0.86100 1.00000 0.00291 MgM2 0.37830 0.48210 0.35230 0.66000 0.00291 FeM2 0.37830 0.48210 0.35230 0.24000 0.00291 CaM2 0.37830 0.48210 0.35230 0.01200 0.00291 AlM2 0.37830 0.48210 0.35230 0.08000 0.00291 SiTA 0.26900 0.34330 0.04350 0.97000 0.00114 AlTA 0.26900 0.34330 0.04350 0.03000 0.00114 SiTB 0.47500 0.33790 0.80310 0.97000 0.00114 AlTB 0.47500 0.33790 0.80310 0.03000 0.00114 O1a 0.17700 0.33900 0.02900 1.00000 0.00317 O2a 0.31100 0.50600 0.03600 1.00000 0.00317 O3a 0.30300 0.22800 0.82100 1.00000 0.00317 O1b 0.56700 0.34100 0.80900 1.00000 0.00317 O2b 0.43200 0.48800 0.69100 1.00000 0.00317 O3b 0.45100 0.19100 0.61100 1.00000 0.00317