data_global _chemical_name_mineral 'Vermiculite' loop_ _publ_author_name 'Mathieson A M' 'Walker G F' _journal_name_full 'American Mineralogist' _journal_volume 39 _journal_year 1954 _journal_page_first 231 _journal_page_last 255 _publ_section_title ; Crystal structure of magnesium-vermiculite ; _database_code_amcsd 63 _chemical_formula_sum 'Mg1.338 Fe.24 Al.721 Si1.36 O9 H3' _cell_length_a 5.33 _cell_length_b 9.18 _cell_length_c 28.9 _cell_angle_alpha 90.0 _cell_angle_beta 97.0 _cell_angle_gamma 90.0 _cell_volume 1403.52 _exptl_crystal_density_diffrn 1.186 _symmetry_space_group_name_H-M 'C 1 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' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy Mg1 0.0 0.0 0.0 0.393 Fe1 0.0 0.0 0.0 0.08 Al1 0.0 0.0 0.0 0.027 Mg2 0.0 0.333 0.0 0.393 Fe2 0.0 0.333 0.0 0.08 Al2 0.0 0.333 0.0 0.027 Mg3 0.0 0.667 0.0 0.393 Fe3 0.0 0.667 0.0 0.08 Al3 0.0 0.667 0.0 0.027 Si1 0.397 0.0 0.096 0.68 Al4 0.397 0.0 0.096 0.32 Si2 0.397 0.333 0.097 0.68 Al5 0.397 0.333 0.097 0.32 Mg4 0.5 0.0 0.25 0.053 Mg5 0.5 0.333 0.25 0.053 Mg6 0.5 0.667 0.25 0.053 O1 0.358 0.0 0.037 1.0 O2 0.358 0.333 0.037 1.0 O3 0.358 0.667 0.037 1.0 O4 0.147 0.404 0.114 1.0 O5 0.147 0.929 0.114 1.0 O6 0.434 0.167 0.114 1.0 O-H7 0.16 -0.019 0.213 1.0 O-H8 0.16 0.352 0.213 1.0 O-H9 0.105 0.667 0.213 1.0