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: Full-occupancy model ; _database_code_amcsd 0001054 _chemical_formula_sum '(Fe.069 Al.931) Ca.229 Na.77 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 3.359 _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 0.06900 Al1 0.00000 0.90540 0.25000 0.93100 Ca2 0.00000 0.30090 0.25000 0.22900 Na2 0.00000 0.30090 0.25000 0.77000 Si 0.28950 0.09300 0.22830 1.00000 O1 0.11040 0.07790 0.13090 1.00000 O2 0.36080 0.26010 0.30050 1.00000 O3 0.35290 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 0.00607 0.00495 0.00000 0.00115 0.00000 Al1 0.00501 0.00607 0.00495 0.00000 0.00115 0.00000 Ca2 0.01293 0.00759 0.00710 0.00000 -0.00069 0.00000 Na2 0.01293 0.00759 0.00710 0.00000 -0.00069 0.00000 Si 0.00375 0.00531 0.00380 -0.00040 0.00161 -0.00044 O1 0.00459 0.01100 0.00989 0.00080 0.00207 -0.00110 O2 0.01168 0.00683 0.01014 -0.00159 0.00276 -0.00132 O3 0.00626 0.01062 0.00609 0.00040 0.00230 -0.00241