data_global _chemical_name_mineral 'Phlogopite' loop_ _publ_author_name 'Hendricks S B' 'Jefferson M E' _journal_name_full 'American Mineralogist' _journal_volume 24 _journal_year 1939 _journal_page_first 729 _journal_page_last 771 _publ_section_title ; Polymorphism of the micas with optical measurements Note: data is reproduced from Jackson and West (1930) Note: Biotite group ; _database_code_amcsd 25 _chemical_formula_sum 'K Mg3 (Si3 Al) O11 (F H)' _cell_length_a 5.32 _cell_length_b 9.21 _cell_length_c 20.08 _cell_angle_alpha 90.0 _cell_angle_beta 95.0 _cell_angle_gamma 90.0 _cell_volume 980.12 _exptl_crystal_density_diffrn 2.841 _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 K 0.0 0.083 0.25 1.0 Mg1 0.25 0.083 0.0 1.0 Mg2 0.75 0.25 0.0 1.0 Si1 -0.033 -0.25 0.135 0.75 Si2 -0.033 0.417 0.135 0.75 Al1 -0.033 -0.25 0.135 0.25 Al2 -0.033 0.417 0.135 0.25 O1 0.228 0.333 0.164 1.0 O2 0.228 -0.167 0.164 1.0 O3 0.48 0.083 0.164 1.0 O4 -0.062 -0.167 0.055 1.0 O5 -0.062 0.417 0.055 1.0 O-H -0.062 0.083 0.058 0.5 F -0.062 0.083 0.058 0.5