data_global _chemical_name_mineral 'Vermiculite' loop_ _publ_author_name 'Gruner J W' _journal_name_full 'American Mineralogist' _journal_volume 19 _journal_year 1934 _journal_page_first 557 _journal_page_last 575 _publ_section_title ; The structures of vermiculites and their collapse by dehydration ; _database_code_amcsd 12 _chemical_compound_source 'Structure results from data of many samples' _chemical_formula_sum 'Mg3 Si4 (O12 H2)' _cell_length_a 5.31 _cell_length_b 9.2 _cell_length_c 28.46 _cell_angle_alpha 90.0 _cell_angle_beta 97.14 _cell_angle_gamma 90.0 _cell_volume 1379.547 _exptl_crystal_density_diffrn 1.826 _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 Mg1 0.0 0.0 0.0 Mg2 0.0 0.333333 0.0 Mg3 0.0 0.666667 0.0 Si1 0.397 0.0 0.094 Si2 0.897 0.16667 0.094 Si3 0.603 0.0 0.406 Si4 0.103 0.16667 0.406 O-H1 0.858 0.83333 0.039 O-H2 0.142 0.83333 0.461 O1 0.858 0.5 0.039 O2 0.858 0.16667 0.039 O3 0.161 0.08333 0.115 O4 0.661 0.08333 0.115 O5 0.911 0.333333 0.115 O6 0.839 0.08333 0.385 O7 0.339 0.08333 0.385 O8 0.089 0.333333 0.385 O9 0.142 0.5 0.461 O10 0.142 0.16667 0.461