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 = 1.90 GPa, natural orthopyroxene ; _database_code_amcsd 0008020 _chemical_formula_sum 'Mg1.66 Fe.24 Ca.012 Al.14 Si1.94 O6' _cell_length_a 18.160 _cell_length_b 8.7503 _cell_length_c 5.1606 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 820.047 _exptl_crystal_density_diffrn 3.377 _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 0.37600 0.65410 0.86300 1.00000 0.00127 MgM2 0.37920 0.48300 0.35460 0.66000 0.00127 FeM2 0.37920 0.48300 0.35460 0.24000 0.00127 CaM2 0.37920 0.48300 0.35460 0.01200 0.00127 AlM2 0.37920 0.48300 0.35460 0.08000 0.00127 SiTA 0.26800 0.34240 0.04580 0.97000 0.00063 AlTA 0.26800 0.34240 0.04580 0.03000 0.00063 SiTB 0.47520 0.33710 0.80250 0.97000 0.00063 AlTB 0.47520 0.33710 0.80250 0.03000 0.00063 O1a 0.17900 0.34300 0.02400 1.00000 0.00342 O2a 0.30900 0.50600 0.04200 1.00000 0.00342 O3a 0.30100 0.22300 0.81900 1.00000 0.00342 O1b 0.56600 0.33900 0.81400 1.00000 0.00342 O2b 0.42900 0.48500 0.69200 1.00000 0.00342 O3b 0.44500 0.19200 0.60900 1.00000 0.00342