data_global
_chemical_name_mineral 'Sillimanite'
loop_
_publ_author_name
'Winter J K'
'Ghose S'
_journal_name_full 'American Mineralogist'
_journal_volume 64 
_journal_year 1979
_journal_page_first 573
_journal_page_last 586
_publ_section_title
;
 Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs
 T = 1000 deg C
;
_database_code_amcsd 0000727
_chemical_formula_sum 'Al2 Si O5'
_cell_length_a 7.503
_cell_length_b 7.739
_cell_length_c 5.804
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 337.013
_exptl_crystal_density_diffrn      3.194
_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
Al1   0.00000   0.00000   0.00000
Al2   0.14100   0.34630   0.25000
Si   0.15200   0.34130   0.75000
O1   0.35960   0.41060   0.75000
O2   0.35660   0.43630   0.25000
O3   0.47830   0.00060   0.75000
O4   0.12480   0.22490   0.51420
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
Al1 0.01426 0.01881 0.01536 0.00000 -0.00044 -0.00046
Al2 0.01483 0.01972 0.01638 -0.00088 0.00000 0.00000
Si 0.01255 0.01729 0.01502 -0.00206 0.00000 0.00000
O1 0.01483 0.02518 0.01997 -0.00706 0.00000 0.00000
O2 0.01454 0.02882 0.01741 -0.00618 0.00000 0.00000
O3 0.03679 0.03398 0.04420 -0.02118 0.00000 0.00000
O4 0.02595 0.01881 0.01604 -0.00647 -0.00132 -0.00023