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