data_global
_chemical_name_mineral 'Paracelsian'
loop_
_publ_author_name
'Smith J V'
_journal_name_full 'Acta Crystallographica'
_journal_volume 6 
_journal_year 1953
_journal_page_first 613
_journal_page_last 620
_publ_section_title
;
 The crystal structure of paracelsian, BaAl2Si2O8
;
_database_code_amcsd 0009156
_chemical_compound_source 'Benallt Mine, near Rhiw, Carnarvonshire, U.K.'
_chemical_formula_sum 'Ba (Al2 Si2) O8'
_cell_length_a 9.076
_cell_length_b 9.583
_cell_length_c 8.578
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 746.074
_exptl_crystal_density_diffrn      3.343
_symmetry_space_group_name_H-M 'P n a 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
Ba   0.89730   0.41230   0.25000   1.00000
Al1   0.06500   0.19610   0.93540   0.50000
Si1   0.06500   0.19610   0.93540   0.50000
Al2   0.22830   0.91730   0.93370   0.50000
Si2   0.22830   0.91730   0.93370   0.50000
O1   0.19300   0.08830   0.99800   1.00000
O2   0.12870   0.36200   0.95400   1.00000
O3   0.92500   0.18750   0.06460   1.00000
O4   0.00670   0.17300   0.75000   1.00000
O5   0.29100   0.91200   0.75000   1.00000