data_global
_chemical_name_mineral 'Sillimanite'
loop_
_publ_author_name
'Bish D L'
'Burnham C W'
_journal_name_full 'American Mineralogist'
_journal_volume 77 
_journal_year 1992
_journal_page_first 374
_journal_page_last 379
_publ_section_title
;
 Rietveld refinement of the crystal structure of fibrolitic sillimanite using
 neutron powder diffraction data
;
_database_code_amcsd 0001446
_chemical_formula_sum 'Al2 Si O5'
_cell_length_a 7.4841
_cell_length_b 7.6720
_cell_length_c 5.7707
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 331.342
_exptl_crystal_density_diffrn      3.248
_symmetry_space_group_name_H-M 'P b n m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,y,1/2-z'
  '-x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '1/2-x,1/2+y,1/2-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
Al1   0.00000   0.00000   0.00000   1.00000   0.00210
Al2   0.14280   0.34330   0.25000   0.91000   0.00310
Si2   0.14280   0.34330   0.25000   0.09000   0.00310
Si3   0.15240   0.34120   0.75000   0.91000   0.00280
Al3   0.15240   0.34120   0.75000   0.09000   0.00280
OA   0.36070   0.40690   0.75000   1.00000   0.00170
OB   0.35540   0.43610   0.25000   1.00000   0.00230
OC   0.47830   0.00350   0.75000   1.00000   0.00870
OD   0.12560   0.22220   0.51310   1.00000   0.00330