data_9000714
_chemical_name '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
;
_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
_symmetry_space_group_name_H-M 'P b n m'
loop_
_symmetry_equiv_pos_as_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