data_global
_chemical_name_mineral 'Natrotantite'
loop_
_publ_author_name
'Ercit T S'
'Hawthorne F C'
'Cerny P'
_journal_name_full 'Bulletin de Mineralogie'
_journal_volume 108 
_journal_year 1985
_journal_page_first 541
_journal_page_last 549
_publ_section_title
;
 The crystal structure of synthetic natrotantite
;
_database_code_amcsd 0012086
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Na2 Ta4 O11'
_cell_length_a 6.2092
_cell_length_b 6.2092
_cell_length_c 36.6190
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 1222.668
_exptl_crystal_density_diffrn      7.707
_symmetry_space_group_name_H-M 'R -3 c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '2/3+x,1/3+y,1/3+z'
  '1/3+x,2/3+y,2/3+z'
  'x,x-y,1/2+z'
  '2/3+x,1/3+x-y,5/6+z'
  '1/3+x,2/3+x-y,1/6+z'
  'y,x,1/2-z'
  '2/3+y,1/3+x,5/6-z'
  '1/3+y,2/3+x,1/6-z'
  '-x+y,y,1/2+z'
  '2/3-x+y,1/3+y,5/6+z'
  '1/3-x+y,2/3+y,1/6+z'
  '-x,-x+y,1/2-z'
  '2/3-x,1/3-x+y,5/6-z'
  '1/3-x,2/3-x+y,1/6-z'
  '-y,-x,1/2+z'
  '2/3-y,1/3-x,5/6+z'
  '1/3-y,2/3-x,1/6+z'
  'x-y,-y,1/2-z'
  '2/3+x-y,1/3-y,5/6-z'
  '1/3+x-y,2/3-y,1/6-z'
  'y,-x+y,-z'
  '2/3+y,1/3-x+y,1/3-z'
  '1/3+y,2/3-x+y,2/3-z'
  '-x+y,-x,z'
  '2/3-x+y,1/3-x,1/3+z'
  '1/3-x+y,2/3-x,2/3+z'
  '-x,-y,-z'
  '2/3-x,1/3-y,1/3-z'
  '1/3-x,2/3-y,2/3-z'
  '-y,x-y,z'
  '2/3-y,1/3+x-y,1/3+z'
  '1/3-y,2/3+x-y,2/3+z'
  'x-y,x,-z'
  '2/3+x-y,1/3+x,1/3-z'
  '1/3+x-y,2/3+x,2/3-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Na   0.00000   0.00000   0.33230   0.03926
Ta1   0.36410   0.00000   0.25000   0.03977
Ta2   0.00000   0.00000   0.00000   0.04255
O1   0.05200   0.41400   0.19750   0.02786
O2   0.75000   0.00000   0.25000   0.04559
O3   0.00000   0.00000   0.40740   0.02280