data_global _chemical_name_mineral 'Enstatite' loop_ _publ_author_name 'Angel R J' 'Chopelas A' 'Ross N L' _journal_name_full 'Nature' _journal_volume 358 _journal_year 1992 _journal_page_first 322 _journal_page_last 324 _publ_section_title ; Stability of high-density clinoenstatite at upper-mantle pressures Sample: P = 7.93 GPa ; _database_code_amcsd 0014680 _chemical_formula_sum 'Si Mg O3' _cell_length_a 9.201 _cell_length_b 8.621 _cell_length_c 4.908 _cell_angle_alpha 90 _cell_angle_beta 101.50 _cell_angle_gamma 90 _cell_volume 381.496 _exptl_crystal_density_diffrn 3.496 _symmetry_space_group_name_H-M 'C 1 2/c 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' 'x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '-x,y,1/2-z' '1/2-x,1/2+y,1/2-z' '-x,-y,-z' '1/2-x,1/2-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv Si 0.29880 0.09150 0.21120 0.00367 Mg1 0.00000 0.90570 0.25000 0.00469 Mg2 0.00000 0.27420 0.25000 0.00722 O1 0.12150 0.09140 0.13900 0.00507 O2 0.38000 0.23760 0.36700 0.00507 O3 0.35700 0.06130 0.91500 0.00380