data_1000504
_chemical_name_systematic
;
Disodium magnesium digadolinium catena-tetrasilicate difluoride
;
_chemical_formula_structural       'Na2 Mg Gd2 (Si4 O12) F2'
_chemical_formula_sum              'F2 Gd2 Mg Na2 O12 Si4'
_publ_section_title
;
The crystal structure of Na2 Mg Gd2 (Si4 O12) F2 and its relationship
with leucophanite
;
loop_
_publ_author_name
  'Maisonneuve, V'
  'Leblanc, M'
_journal_name_full                 'Canadian Mineralogist'
_journal_coden_ASTM                CAMIA6
_journal_volume                    36
_journal_year                      1998
_journal_page_first                1039
_journal_page_last                 1043
_cell_length_a                     5.178(3)
_cell_length_b                     7.510(2)
_cell_length_c                     14.381(4)
_cell_angle_alpha                  90
_cell_angle_beta                   90.22(2)
_cell_angle_gamma                  90
_cell_volume                       559.2
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'P 1 21/c 1'
_symmetry_Int_Tables_number        14
_symmetry_cell_setting             monoclinic
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-x,1/2+y,1/2-z'
  '-x,-y,-z'
  'x,1/2-y,1/2+z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Gd3+   3.000
  Si4+   4.000
  Mg2+   2.000
  Na1+   1.000
  F1-   -1.000
  O2-   -2.000
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_attached_hydrogens
_atom_site_calc_flag
  Gd1   Gd3+   4 e 0.51375(5) 0.22882(3) 0.95706(2) 1.  0 d
  Si1   Si4+   4 e 0.0231(3) 0.2407(2) 0.8140(1) 1.  0 d
  Si2   Si4+   4 e 0.0370(3) 0.3718(2) 0.6149(1) 1.  0 d
  Mg1   Mg2+   2 c 0. 0. 0.5 1.  0 d
  Na1   Na1+   4 e 0.5040(6) 0.4570(5) 0.2106(2) 1.  0 d
  F1    F1-    4 e 0.3366(7) 0.4607(5) 0.0610(2) 1.  0 d
  O1    O2-    4 e 0.1443(8) 0.2726(6) 0.7098(3) 1.  0 d
  O2    O2-    4 e 0.7152(8) 0.2423(5) 0.8137(3) 1.  0 d
  O3    O2-    4 e 0.1390(8) 0.0418(5) 0.8471(3) 1.  0 d
  O4    O2-    4 e 0.1636(8) 0.3733(6) 0.8853(3) 1.  0 d
  O5    O2-    4 e 0.8602(8) 0.2398(5) 0.5535(3) 1.  0 d
  O6    O2-    4 e 0.2868(8) 0.4433(5) 0.5595(3) 1.  0 d
_refine_ls_R_factor_all            0.039