data_global
_chemical_name_mineral 'Biotite'
loop_
_publ_author_name
'Takeda H'
'Ross M'
_journal_name_full 'American Mineralogist'
_journal_volume 60
_journal_year 1975
_journal_page_first 1030
_journal_page_last 1040
_publ_section_title
;
 Mica polytypism: Dissimilarities in the crystal structures of coexisting 1M and
 2M1 biotite
;
_database_code_amcsd 478
_chemical_formula_sum 'Mg2.001 Al1.999 K Si3 O12 H2'
_cell_length_a 5.331
_cell_length_b 9.231
_cell_length_c 10.173
_cell_angle_alpha 90.0
_cell_angle_beta 100.16
_cell_angle_gamma 90.0
_cell_volume 492.768
_exptl_crystal_density_diffrn  2.83
_symmetry_space_group_name_H-M 'C 1 2/m 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,z'
  '1/2+x,1/2-y,z'
  '-x,y,-z'
  '1/2-x,1/2+y,-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Mg1   0.0  0.0  0.5  0.667
Mg2   0.0  0.3392  0.5  0.667
Al1   0.0  0.0  0.5  0.333
Al2   0.0  0.3392  0.5  0.333
K1   0.0  0.5  0.0  1.0
Si1   0.0745  0.1671  0.2242  0.75
Al3   0.0745  0.1671  0.2242  0.25
O1   0.0165  0.0  0.1674  1.0
O2   0.324  0.231  0.166  1.0
O3   0.131  0.1684  0.3906  1.0
O-H4   0.1312  0.5  0.3985  1.0
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Mg1   0.01186  0.0082  0.0254  0.0  0.00612  0.0
Mg2   0.00893  0.01425  0.02083  0.0  0.00319  0.0
Al1   0.01186  0.0082  0.0254  0.0  0.00612  0.0
Al2   0.00893  0.01425  0.02083  0.0  0.00319  0.0
K1   0.02511  0.02288  0.04013  0.0  0.00745  0.0
Si1   0.00767  0.00548  0.0157  0.0  0.00346  0.0
Al3   0.00767  0.00548  0.0157  0.0  0.00346  0.0
O1   0.02399  0.01036  0.02083  0.0  0.00346  0.0
O2   0.01604  0.01899  0.0254  -0.00417  0.00453  -0.00281
O3   0.01032  0.00777  0.01676  0.00074  0.00399  0.0
O-H4   0.01102  0.01209  0.01575  0.0  0.00213  0.0