data_global _chemical_name_mineral 'Omphacite' loop_ _publ_author_name 'Clark J R' 'Papike J J' _journal_name_full 'American Mineralogist' _journal_volume 53 _journal_year 1968 _journal_page_first 840 _journal_page_last 868 _publ_section_title ; Crystal-chemical characterization of omphacites ; _database_code_amcsd 175 _chemical_formula_sum 'Si4 Mg.805 Fe.31 Al.885 (Na.835 Ca1.165) O12' _cell_length_a 9.596 _cell_length_b 8.771 _cell_length_c 5.265 _cell_angle_alpha 90.0 _cell_angle_beta 106.93 _cell_angle_gamma 90.0 _cell_volume 423.932 _exptl_crystal_density_diffrn 3.376 _symmetry_space_group_name_H-M 'P 1 2 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '-x,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 Si1A 0.289 0.0972 0.9774 1.0 0.00215 Si2A 0.2881 0.9135 0.482 1.0 0.00215 Si1C 0.2137 0.588 0.0196 1.0 0.00215 Si2C 0.2103 0.4027 0.5232 1.0 0.00215 Mg1 0.0 0.9122 0.0 0.81 0.00253 Fe1 0.0 0.9122 0.0 0.19 0.00253 Al11 0.0 0.1002 0.5 0.95 0.0038 Fe11 0.0 0.1002 0.5 0.05 0.0038 Al1H 0.5 0.4045 0.0 0.82 0.0038 Fe1H 0.5 0.4045 0.0 0.18 0.0038 Mg11H 0.5 0.5957 0.5 0.8 0.00253 Fe11H 0.5 0.5957 0.5 0.2 0.00253 Na2 0.0 0.3036 0.0 0.64 0.01013 Ca2 0.0 0.3036 0.0 0.36 0.01013 Na21 0.0 0.7017 0.5 0.36 0.00887 Ca21 0.0 0.7017 0.5 0.64 0.00887 Na2H 0.5 0.8009 0.0 0.03 0.01013 Ca2H 0.5 0.8009 0.0 0.97 0.01013 Na21H 0.5 0.1996 0.5 0.64 0.01013 Ca21H 0.5 0.1996 0.5 0.36 0.01013 O11A 0.112 0.088 0.864 1.0 0.00507 O12A 0.11 0.922 0.405 1.0 0.00507 O11C 0.386 0.567 0.103 1.0 0.00507 O12C 0.385 0.411 0.62 1.0 0.00507 O21A 0.364 0.263 0.066 1.0 0.00507 O22A 0.347 0.747 0.551 1.0 0.00507 O21C 0.133 0.749 0.939 1.0 0.00507 O22C 0.135 0.244 0.446 1.0 0.00507 O31A 0.36 0.022 0.757 1.0 0.00507 O32A 0.35 0.994 0.252 1.0 0.00507 O31C 0.154 0.515 0.255 1.0 0.00507 O32C 0.147 0.489 0.75 1.0 0.00507