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 479
_chemical_formula_sum 'Mg2.001 Al1.999 K.5 Si3 O12'
_cell_length_a 5.329
_cell_length_b 9.234
_cell_length_c 20.098
_cell_angle_alpha 90.0
_cell_angle_beta 95.09
_cell_angle_gamma 90.0
_cell_volume 985.082
_exptl_crystal_density_diffrn  2.686
_symmetry_space_group_name_H-M 'C 1 2/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'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-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   0.75  0.25  0.0  0.667
Al1   0.75  0.25  0.0  0.333
Mg2   0.2406  0.0802  -4e-05  0.667
Al2   0.2406  0.0802  -4e-05  0.333
K   0.0  0.084  0.25  0.5
Si1   0.4621  0.2498  0.138  0.75
Al3   0.4621  0.2498  0.138  0.25
Si2   0.9635  0.4169  0.138  0.75
Al4   0.9635  0.4169  0.138  0.25
O1   0.741  0.314  0.1662  1.0
O2   0.243  0.3532  0.1672  1.0
O3   0.4337  0.084  0.1666  1.0
O4   0.4314  0.2406  0.0545  1.0
O5   0.9375  0.409  0.0547  1.0
O6   0.9348  0.0739  0.0508  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   0.00785  0.0108  0.01421  0.0  0.00161  0.0
Al1   0.00785  0.0108  0.01421  0.0  0.00161  0.0
Mg2   0.0157  0.01123  0.01218  0.00497  0.00108  0.00187
Al2   0.0157  0.01123  0.01218  0.00497  0.00108  0.00187
K   0.02598  0.02808  0.03045  0.0  0.00161  0.0
Si1   0.00742  0.00994  0.01015  0.00074  0.00054  0.00094
Al3   0.00742  0.00994  0.01015  0.00074  0.00054  0.00094
Si2   0.00756  0.0095  0.01015  -0.00149  0.00108  -0.00187
Al4   0.00756  0.0095  0.01015  -0.00149  0.00108  -0.00187
O1   0.01941  0.02333  0.01624  -0.00472  0.0  0.00094
O2   0.01542  0.02592  0.01624  0.00621  0.0  -0.00187
O3   0.02583  0.01641  0.01421  0.00074  0.00215  0.0
O4   0.00671  0.00302  0.01218  0.00025  0.00161  0.00375
O5   0.00999  0.00605  0.01015  0.00273  0.00108  0.00468
O6   0.01256  0.00475  0.01218  0.00223  0.0  0.0