data_global _chemical_name_mineral 'Diopside' loop_ _publ_author_name 'Bertolo S' 'Nimis P' 'Dal Negro A' _journal_name_full 'American Mineralogist' _journal_volume 79 _journal_year 1994 _journal_page_first 668 _journal_page_last 674 _publ_section_title ; Low-Ca augite from experimental alkali basalt at 18 kbar: Structural variation near the miscibility gap Atomic parameters from ICSD ; _database_code_amcsd 0001667 _chemical_formula_sum '(Ca.774 Na.226) Mg.901 Fe.11 Si2 O6' _cell_length_a 9.689 _cell_length_b 8.824 _cell_length_c 5.280 _cell_angle_alpha 90 _cell_angle_beta 107.60 _cell_angle_gamma 90 _cell_volume 430.287 _exptl_crystal_density_diffrn 3.341 _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 Ca 0.00000 0.28740 0.25000 0.77400 ? Na 0.00000 0.28740 0.25000 0.22600 ? Mg 0.00000 0.90560 0.25000 0.90100 ? Fe1 0.00000 0.90560 0.25000 0.09900 ? Si 0.29170 0.09180 0.24140 1.00000 ? O1 0.11540 0.08680 0.14130 1.00000 ? O2 0.36790 0.25220 0.33290 1.00000 ? O3 0.35340 0.01740 0.00880 1.00000 ? Fe2 0.00000 0.22290 0.25000 0.01100 0.02500 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 Ca 0.02080 0.03250 0.01960 0.00000 0.00200 0.00000 Na 0.02080 0.03250 0.01960 0.00000 0.00200 0.00000 Mg 0.01300 0.01060 0.01620 0.00000 0.00360 0.00000 Fe1 0.01300 0.01060 0.01620 0.00000 0.00360 0.00000 Si 0.01330 0.01100 0.02070 -0.00020 0.00560 -0.00120 O1 0.01430 0.01700 0.02170 0.00190 0.00490 -0.00100 O2 0.02690 0.01450 0.03340 -0.00420 0.01430 -0.00640 O3 0.01470 0.03680 0.03660 -0.00080 0.00590 -0.01910