data_Vermiculite _chemical_name_systematic 'Trimagnesium dihydrogen phyllo-silicate' _chemical_name_mineral 'Vermiculite' _chemical_formula_structural 'Mg3 Si4 O10 (O H)2' _chemical_formula_sum 'H2 Mg3 O12 Si4' _publ_section_title ; Crystal structure of vermiculites and mixed vermiculite-chlorites ; loop_ _publ_author_name 'Hendricks, S B' 'Jefferson, M E' _journal_name_full 'American Mineralogist' _journal_coden_ASTM AMMIAY _journal_volume 23 _journal_year 1938 _journal_page_first 851 _journal_page_last 862 _cell_length_a 5.33(5) _cell_length_b 9.18(5) _cell_length_c 28.85(10) _cell_angle_alpha 90 _cell_angle_beta 93.25(25) _cell_angle_gamma 90 _cell_volume 1409.3 _cell_formula_units_Z 4 _symmetry_space_group_name_H-M 'C 1 c 1' _symmetry_Int_Tables_number 9 _symmetry_cell_setting monoclinic loop_ _symmetry_equiv_pos_as_xyz 'x,y,z' 'x,-y,1/2+z' '1/2+x,1/2+y,z' '1/2+x,1/2-y,1/2+z' loop_ _atom_type_symbol _atom_type_oxidation_number Mg2+ 2.000 O2- -2.000 Si4+ 4.000 H1+ 1.000 loop_ _atom_site_label _atom_site_type_symbol _atom_site_symmetry_multiplicity _atom_site_Wyckoff_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_attached_hydrogens _atom_site_calc_flag Mg1 Mg2+ 4 a 0. 0. 0. 1. 0 d Mg2 Mg2+ 4 a 0. 0.3333 0. 1. 0 d Mg3 Mg2+ 4 a 0. 0.6667 0. 1. 0 d O1 O2- 4 a 0.18 0.5 0.04 1. 1 d O2 O2- 4 a -0.18 0.8333 -0.04 1. 1 d O3 O2- 4 a 0.18 0.8333 0.04 1. 0 d O4 O2- 4 a -0.18 0.5 -0.04 1. 0 d O5 O2- 4 a 0.18 0.1667 0.04 1. 0 d O6 O2- 4 a -0.18 0.1667 -0.04 1. 0 d O7 O2- 4 a -0.048 0.75 0.115 1. 0 d O8 O2- 4 a 0.048 0.5833 -0.115 1. 0 d O9 O2- 4 a 0.452 0.75 0.115 1. 0 d O10 O2- 4 a -0.452 0.5833 -0.115 1. 0 d O11 O2- 4 a 0.202 0. 0.115 1. 0 d O12 O2- 4 a -0.202 0.3333 -0.115 1. 0 d Si1 Si4+ 4 a 0.196 0.8333 0.095 1. 0 d Si2 Si4+ 4 a -0.196 0.5 -0.095 1. 0 d Si3 Si4+ 4 a -0.304 0.6667 0.095 1. 0 d Si4 Si4+ 4 a 0.304 0.6667 -0.095 1. 0 d H1 H1+ 4 a -1. -1. -1. 2. 0 dum