data_global _chemical_name_mineral 'Diopside' loop_ _publ_author_name 'Oberti R' 'Caporuscio F A' _journal_name_full 'American Mineralogist' _journal_volume 76 _journal_year 1991 _journal_page_first 1141 _journal_page_last 1152 _publ_section_title ; Crystal chemistry of clinopyroxenes from mantle eclogites: A study of the key role of the M2 site population by means of crystal-structure refinement sample SBB 7P, Di78Jd18, diopside - jadeite join ; _database_code_amcsd 0001363 _chemical_formula_sum 'Mg.83 Cr.09 Al.1 Fe.05 Ca.78 Na.18 Si1.97 O6' _cell_length_a 9.693 _cell_length_b 8.889 _cell_length_c 5.253 _cell_angle_alpha 90 _cell_angle_beta 106.34 _cell_angle_gamma 90 _cell_volume 434.323 _exptl_crystal_density_diffrn 3.320 _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_occupancy _atom_site_U_iso_or_equiv Mg1 0.00000 0.90680 0.25000 0.79000 0.00583 Cr1 0.00000 0.90680 0.25000 0.09000 0.00583 Al1 0.00000 0.90680 0.25000 0.07000 0.00583 Fe1 0.00000 0.90680 0.25000 0.05000 0.00583 Ca2 0.00000 0.30080 0.25000 0.78000 0.00963 Na2 0.00000 0.30080 0.25000 0.18000 0.00963 Mg2 0.00000 0.30080 0.25000 0.04000 0.00811 Si 0.28770 0.09270 0.23090 0.98500 0.00443 Al 0.28770 0.09270 0.23090 0.01500 0.00443 O1 0.11500 0.08530 0.14050 1.00000 0.00773 O2 0.36140 0.25190 0.31700 1.00000 0.00988 O3 0.35130 0.01680 -0.00190 1.00000 0.00747