data_9000837
_chemical_name 'Muscovite'
loop_
_publ_author_name
'Richardson S M'
'Richardson J W'
_journal_name_full "American Mineralogist"
_journal_volume 67
_journal_year 1982
_journal_page_first 69
_journal_page_last 75
_publ_section_title
;
 Crystal structure of a pink muscovite from Archer's Post, Kenya: Implications
 for reverse pleochroism in dioctahedral micas
;
_chemical_formula_sum 'K Si3 Al3 O12 H.8'
_cell_length_a 5.1988
_cell_length_b 9.0266
_cell_length_c 20.1058
_cell_angle_alpha 90
_cell_angle_beta 95.782
_cell_angle_gamma 90
_cell_volume 938.715
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_symmetry_equiv_pos_as_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
K   0.00000   0.09920   0.25000   1.00000
Si1   0.45100   0.25870   0.13550   0.75000
Al1   0.45100   0.25870   0.13550   0.25000
Si2   0.03540   0.42980   0.36460   0.75000
Al2   0.03540   0.42980   0.36460   0.25000
Al3   0.25060   0.08380   0.00020   1.00000
O1   0.38720   0.25250   0.05430   1.00000
O2   0.03660   0.44310   0.44590   1.00000
O3   0.41780   0.09310   0.16850   1.00000
O4   0.24750   0.37120   0.16850   1.00000
O5   0.25090   0.31320   0.34240   1.00000
O-H6   0.04220   0.06220   0.44920   1.00000