data_global
_amcsd_formula_title 'Pb2Al2Si2O9'
loop_
_publ_author_name
'Dorsam G'
'Liebscher A'
'Wunder B'
'Franz G'
_journal_name_full 'American Mineralogist'
_journal_volume 93 
_journal_year 2008
_journal_page_first 573
_journal_page_last 583
_publ_section_title
;
 Crystal structures of synthetic melanotekite (Pb2Fe2Si2O9), kentrolite
 (Pb2Mn2Si2O9), and the aluminum analogue (Pb2Al2Si2O9)
;
_database_code_amcsd 0004537
_chemical_formula_sum 'Pb2 Al2 Si2 O9'
_cell_length_a 6.8981
_cell_length_b 10.6906
_cell_length_c 9.7413
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 718.370
_exptl_crystal_density_diffrn      6.181
_symmetry_space_group_name_H-M 'P b c n'
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,z'
  '1/2+x,1/2-y,-z'
  '1/2+x,1/2+y,1/2-z'
  '1/2-x,1/2-y,1/2+z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Pb   0.45060   0.30435   0.54954   0.01230
Al1   0.50000   0.00000   0.00000   0.00600
Al2   0.50000   0.14670   0.25000   0.00700
Si   0.21710  -0.08830   0.24880   0.00700
O1   0.34770   0.00820   0.33720   0.00800
O2   0.30800  -0.10680   0.09650   0.01100
O3   0.18540  -0.22600   0.31690   0.00900
O4   0.00000  -0.02270   0.25000   0.01000
O5   0.60960   0.14100   0.42300   0.00800
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
Pb 0.01370 0.01530 0.00790 -0.00100 -0.00060 -0.00010
Al1 0.00500 0.01040 0.00210 -0.00010 -0.00030 0.00140
Al2 0.00660 0.01080 0.00270 0.00000 -0.00120 0.00000
Si 0.00530 0.01290 0.00360 0.00050 0.00010 -0.00090
O1 0.00790 0.01420 0.00320 0.00050 0.00090 -0.00060
O2 0.01470 0.01380 0.00380 -0.00210 0.00310 -0.00390
O3 0.00800 0.01030 0.00960 0.00070 0.00130 -0.00360
O4 0.00490 0.00770 0.01800 0.00000 -0.00070 0.00000
O5 0.00660 0.01220 0.00380 0.00070 -0.00180 -0.00130