data_global _chemical_name_mineral 'Omphacite' loop_ _publ_author_name 'McCormick T C' _journal_name_full 'American Mineralogist' _journal_volume 71 _journal_year 1986 _journal_page_first 1434 _journal_page_last 1440 _publ_section_title ; Crystal-chemical aspects of nonstoichiometric pyroxenes Sample: Vacancy model II ; _database_code_amcsd 0001056 _chemical_formula_sum 'Fe.082 Al.758 Mg.205 Ca.286 Na.602 Si2 O6' _cell_length_a 9.501 _cell_length_b 8.654 _cell_length_c 5.238 _cell_angle_alpha 90 _cell_angle_beta 107.23 _cell_angle_gamma 90 _cell_volume 411.350 _exptl_crystal_density_diffrn 3.350 _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 Fe1 0.00000 0.90540 0.25000 0.06300 Al1 0.00000 0.90540 0.25000 0.75800 Mg1 0.00000 0.90540 0.25000 0.17900 Fe2 0.00000 0.30090 0.25000 0.01900 Ca2 0.00000 0.30090 0.25000 0.28600 Mg2 0.00000 0.30090 0.25000 0.02600 Na2 0.00000 0.30090 0.25000 0.60200 Si 0.28947 0.09297 0.22831 1.00000 O1 0.11043 0.07790 0.13090 1.00000 O2 0.36080 0.26010 0.30050 1.00000 O3 0.35291 0.01080 0.00340 1.00000 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 Fe1 0.00501 0.00611 0.00495 0.00000 0.00122 0.00000 Al1 0.00501 0.00611 0.00495 0.00000 0.00122 0.00000 Mg1 0.00501 0.00611 0.00495 0.00000 0.00122 0.00000 Fe2 0.01306 0.00774 0.00710 0.00000 -0.00071 0.00000 Ca2 0.01306 0.00774 0.00710 0.00000 -0.00071 0.00000 Mg2 0.01306 0.00774 0.00710 0.00000 -0.00071 0.00000 Na2 0.01293 0.00774 0.00710 0.00000 -0.00071 0.00000 Si 0.00392 0.00520 0.00380 -0.00024 0.00149 -0.00037 O1 0.00442 0.01100 0.00989 0.00064 0.00207 -0.00110 O2 0.01164 0.00694 0.01014 -0.00179 0.00276 -0.00132 O3 0.00609 0.01062 0.00609 0.00048 0.00230 -0.00241