data_global
_chemical_name_mineral 'Cronstedtite'
loop_
_publ_author_name
'Hendricks S B'
_journal_name_full 'American Mineralogist'
_journal_volume 24
_journal_year 1939
_journal_page_first 529
_journal_page_last 539
_publ_section_title
;
 Random structures of layer minerals as illustrated by cronstedtite
 (2FeO.Fe2O3.SiO2.2H2O). Possible iron content of kaolin
;
_database_code_amcsd 22
_chemical_formula_sum 'Si.5 Fe1.4 O4.001 H1.667'
_cell_length_a 3.16
_cell_length_b 3.16
_cell_length_c 21.25
_cell_angle_alpha 90.0
_cell_angle_beta 90.0
_cell_angle_gamma 120.0
_cell_volume 183.765
_exptl_crystal_density_diffrn  4.281
_symmetry_space_group_name_H-M 'R 3'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '2/3+x,1/3+y,1/3+z'
  '1/3+x,2/3+y,2/3+z'
  '-y,x-y,z'
  '2/3-y,1/3+x-y,1/3+z'
  '1/3-y,2/3+x-y,2/3+z'
  '-x+y,-x,z'
  '2/3-x+y,1/3-x,1/3+z'
  '1/3-x+y,2/3-x,2/3+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Si   0.0  0.0  0.03  0.5
Fe   0.0  0.0  0.03  0.5
Fe   0.0  0.0  0.83  0.9
O1   0.0  0.0  0.11  0.333
O-H1   0.0  0.0  0.11  0.667
O-H2   0.0  0.0  0.54  1.0
O2   0.5  0.0  0.0  0.667