data_global
_chemical_name_mineral 'Vermiculite'
loop_
_publ_author_name
'Hendricks S B'
'Jefferson M E'
_journal_name_full 'American Mineralogist'
_journal_volume 23
_journal_year 1938
_journal_page_first 851
_journal_page_last 862
_publ_section_title
;
 Crystal structure of vermiculites and mixed vermiculite-chlorites
;
_database_code_amcsd 19
_chemical_formula_sum 'Mg3 (O12 Si4) H2'
_cell_length_a 5.33
_cell_length_b 9.18
_cell_length_c 28.85
_cell_angle_alpha 90.0
_cell_angle_beta 93.25
_cell_angle_gamma 90.0
_cell_volume 1409.343
_exptl_crystal_density_diffrn  1.787
_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
O-H1   0.18  0.5  0.04
O-H2   -0.18  0.83333  -0.04
O1   0.18  0.83333  0.04
O2   -0.18  0.5  -0.04
O3   0.18  0.16667  0.04
O4   -0.18  0.16667  -0.04
O5   -0.048  0.75  0.115
O6   0.048  0.5833  -0.115
O7   0.452  0.75  0.115
O8   -0.452  0.5833  -0.115
O9   0.202  0.0  0.115
O10   -0.202  0.333333  -0.115
Si1   0.196  0.83333  0.095
Si2   -0.196  0.5  -0.095
Si3   -0.304  0.666667  0.095
Si4   0.304  0.666667  -0.095