data_global
_chemical_name_mineral 'Weberite'
loop_
_publ_author_name
'Giuseppetti G'
'Tadini C'
_journal_name_full 'Tschermaks Mineralogische und Petrographische Mitteilungen'
_journal_volume 25 
_journal_year 1978
_journal_page_first 57
_journal_page_last 62
_publ_section_title
;
 Re-examination of the crystal structure of weberite
;
_database_code_amcsd 0015669
_chemical_compound_source 'Ivigtut, Greenland'
_chemical_formula_sum 'Na2 Mg Al F7'
_cell_length_a 7.060
_cell_length_b 10.000
_cell_length_c 7.303
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 515.592
_exptl_crystal_density_diffrn      2.966
_symmetry_space_group_name_H-M 'I m m a'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,1/2+z'
  'x,1/2-y,z'
  '1/2+x,-y,1/2+z'
  '-x,1/2+y,-z'
  '1/2-x,+y,1/2-z'
  '-x,y,z'
  '1/2-x,1/2+y,1/2+z'
  'x,-y,-z'
  '1/2+x,1/2-y,1/2-z'
  'x,1/2+y,-z'
  '1/2+x,+y,1/2-z'
  '-x,1/2-y,z'
  '1/2-x,-y,1/2+z'
  '-x,-y,-z'
  '1/2-x,1/2-y,1/2-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Na1   0.00000   0.00000   0.00000   0.02178
Na2   0.25000   0.25000   0.75000   0.02850
Mg1   0.25000   0.25000   0.25000   0.00570
Al1   0.00000   0.00000   0.50000   0.00393
F1   0.00000   0.25000   0.13620   0.00988
F2   0.00000   0.41450   0.72050   0.01140
F3   0.18360   0.38730   0.43010   0.01102
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
Na1 0.01944 0.03496 0.01108 0.00000 0.00000 0.00999
Na2 0.01389 0.01824 0.05323 0.00000 -0.00470 0.00000
Mg1 0.00429 0.00659 0.00621 0.00000 0.00104 0.00000
Al1 0.00379 0.00456 0.00351 0.00000 0.00000 0.00185
F1 0.00278 0.01672 0.01027 0.00000 0.00000 0.00000
F2 0.01490 0.01317 0.00594 0.00000 0.00000 0.00074
F3 0.00859 0.01115 0.01351 0.00286 0.00131 -0.00592