data_global
_chemical_name_mineral 'Weberite'
loop_
_publ_author_name
'Knop O'
'Cameron T S'
'Jochem K'
_journal_name_full 'Journal of Solid State Chemistry'
_journal_volume 43 
_journal_year 1982
_journal_page_first 213
_journal_page_last 221
_publ_section_title
;
 What is the true space group of weberite?
 Sample: Imm2 refinement, T = ambient
;
_database_code_amcsd 0013479
_chemical_compound_source 'Ivigtut, Greenland'
_chemical_formula_sum 'Na2 Mg Al F7'
_cell_length_a 7.051
_cell_length_b 9.968
_cell_length_c 7.285
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 512.022
_exptl_crystal_density_diffrn      2.987
_symmetry_space_group_name_H-M 'I m m 2'
loop_
_space_group_symop_operation_xyz
  '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,y,z'
  '1/2-x,1/2+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
Na1   0.24920   0.00000   0.49860
Na2   0.00000   0.25340   0.75030
Mg   0.24990   0.00000   0.00000
Al   0.00000   0.24990   0.25030
F1   0.00000   0.00000   0.88440
F2   0.00000   0.50000   0.61190
F3   0.00000   0.16630   0.47000
F4   0.00000   0.33670   0.02820
F5   0.18380   0.13780   0.18050
F6   0.31650   0.13710   0.81980
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 0.01810 0.01960 0.05560 0.00000 -0.00490 0.00000
Na2 0.02290 0.03320 0.01500 0.00000 0.00000 -0.00970
Mg 0.00780 0.00670 0.00750 0.00000 0.00070 0.00000
Al 0.00820 0.00730 0.00760 0.00000 0.00000 -0.00180
F1 0.01090 0.01950 0.01640 0.00000 0.00000 0.00000
F2 0.00560 0.01960 0.00960 0.00000 0.00000 0.00000
F3 0.02220 0.01530 0.01130 0.00000 0.00000 0.00060
F4 0.01510 0.01740 0.00840 0.00000 0.00000 0.00200
F5 0.01290 0.01590 0.01540 -0.00010 0.00140 -0.00940
F6 0.01360 0.01090 0.01890 -0.00670 0.00220 0.00260