data_global _chemical_name_mineral 'Vermiculite' loop_ _publ_author_name 'de la Calle C' 'Pezerat H' 'Gasperin M' _journal_name_full 'Journal de Physique' _journal_volume 38 _journal_year 1977 _journal_page_first 128 _journal_page_last 133 _publ_section_title ; Problemes d'ordre-desordre dans les vermiculites structure du mineral calcique hydrate a 2 couches _cod_database_code 1001031 ; _database_code_amcsd 0012759 _chemical_formula_sum 'Si2.764 Al1.68 Fe.207 Mg2.022 Ti.042 O15.16 Ca.43' _cell_length_a 5.351 _cell_length_b 9.262 _cell_length_c 15.03 _cell_angle_alpha 90 _cell_angle_beta 96.83 _cell_angle_gamma 90 _cell_volume 739.615 _exptl_crystal_density_diffrn 2.000 _symmetry_space_group_name_H-M 'C 1 2/m 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,z' 'x,-y,z' '1/2+x,1/2-y,z' '-x,y,-z' '1/2-x,1/2+y,-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 Si1 0.39400 0.16700 0.18300 0.69100 Al1 0.39400 0.16700 0.18300 0.29400 Fe1 0.39400 0.16700 0.18300 0.01500 Mg1 0.00000 0.16700 0.00000 0.67400 Al2 0.00000 0.16700 0.00000 0.16800 Fe2 0.00000 0.16700 0.00000 0.02100 Fe3 0.00000 0.16700 0.00000 0.02800 Ti1 0.00000 0.16700 0.00000 0.01400 Mg2 0.00000 0.50000 0.00000 0.67400 Al3 0.00000 0.50000 0.00000 0.16800 Fe4 0.00000 0.50000 0.00000 0.02100 Fe5 0.00000 0.50000 0.00000 0.02800 Ti2 0.00000 0.50000 0.00000 0.01400 O1 0.85500 0.00000 0.06400 1.00000 O2 0.35300 0.16700 0.07700 1.00000 O3 0.13800 0.23100 0.22200 1.00000 O4 0.44400 0.00000 0.21600 1.00000 Ca1 0.00000 0.33300 0.50000 0.11500 Ca2 0.00000 0.03600 0.50000 0.10000 O5 0.12000 0.14100 0.40000 0.22000 O6 0.27000 0.35500 0.40800 0.11000 O7 0.45000 0.50000 0.34200 0.20000 O8 0.45000 0.00000 0.49000 0.20000 O9 0.27000 0.22800 0.41000 0.15000 O10 0.12500 0.50000 0.39100 0.22000