data_global _chemical_name_mineral 'Cronstedtite' loop_ _publ_author_name 'Hendricks S B' _journal_name_full 'American Mineralogist' _journal_volume 24 _journal_year 1939 _journal_page_first 529 _journal_page_last 539 _publ_section_title ; Random structures of layer minerals as illustrated by cronstedtite (2FeO.Fe2O3.SiO2.2H2O). Possible iron content of kaolin ; _database_code_amcsd 22 _chemical_formula_sum 'Si.5 Fe1.4 O4.001 H1.667' _cell_length_a 3.16 _cell_length_b 3.16 _cell_length_c 21.25 _cell_angle_alpha 90.0 _cell_angle_beta 90.0 _cell_angle_gamma 120.0 _cell_volume 183.765 _exptl_crystal_density_diffrn 4.281 _symmetry_space_group_name_H-M 'R 3' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Si 0.0 0.0 0.03 0.5 Fe 0.0 0.0 0.03 0.5 Fe 0.0 0.0 0.83 0.9 O1 0.0 0.0 0.11 0.333 O-H1 0.0 0.0 0.11 0.667 O-H2 0.0 0.0 0.54 1.0 O2 0.5 0.0 0.0 0.667