data_global
_chemical_name_mineral 'Mullite'
loop_
_publ_author_name
'Balzar D'
'Ledbetter H'
_journal_name_full 'American Mineralogist'
_journal_volume 78 
_journal_year 1993
_journal_page_first 1192
_journal_page_last 1196
_publ_section_title
;
 Crystal structure and compressibility of 3:2 mullite
;
_database_code_amcsd 0001618
_chemical_formula_sum 'Al2.25 Si.75 O4.871'
_cell_length_a 7.54336
_cell_length_b 7.69176
_cell_length_c 2.88402
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 167.336
_exptl_crystal_density_diffrn      3.170
_symmetry_space_group_name_H-M 'P b a m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2-y,z'
  '1/2-x,1/2+y,-z'
  '1/2-x,1/2+y,z'
  '1/2+x,1/2-y,-z'
  'x,y,-z'
  '-x,-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
Al   0.00000   0.00000   0.00000   1.00000   0.00291
Al1   0.14850   0.34070   0.50000   0.52500   0.00304
Si1   0.14850   0.34070   0.50000   0.34200   0.00304
Al2   0.26100   0.20730   0.50000   0.10000 ?
Si2   0.26100   0.20730   0.50000   0.03300 ?
O1   0.35770   0.42350   0.50000   1.00000   0.02685
O2   0.50000   0.00000   0.50000   0.47500   0.02609
O3   0.46350   0.04650   0.50000   0.19800   0.05737
O4   0.12650   0.21970   0.00000   1.00000   0.02736