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 0000019
_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
_cell_angle_beta 93.25
_cell_angle_gamma 90
_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   0.00000   0.00000   0.00000
Mg2   0.00000   0.33333   0.00000
Mg3   0.00000   0.66667   0.00000
O-H1   0.18000   0.50000   0.04000
O-H2  -0.18000   0.83333  -0.04000
O1   0.18000   0.83333   0.04000
O2  -0.18000   0.50000  -0.04000
O3   0.18000   0.16667   0.04000
O4  -0.18000   0.16667  -0.04000
O5  -0.04800   0.75000   0.11500
O6   0.04800   0.58330  -0.11500
O7   0.45200   0.75000   0.11500
O8  -0.45200   0.58330  -0.11500
O9   0.20200   0.00000   0.11500
O10  -0.20200   0.33333  -0.11500
Si1   0.19600   0.83333   0.09500
Si2  -0.19600   0.50000  -0.09500
Si3  -0.30400   0.66667   0.09500
Si4   0.30400   0.66667  -0.09500