data_global
_chemical_name_systematic
;
Sodium Aluminium Boron Oxide (2/2/2/7)
;
_chemical_formula_structural       'Na2 Al2 B2 O7'
_chemical_formula_sum              'Al2 B2 Na2 O7'
_publ_section_title
;
Crystal structureand infrared spectra of Li~2~Al~2~B~2~O~7~
;
loop_
_publ_author_name
  'He, M'
  'Chen, X'
  'Zhou, T'
  'Hu, B'
  'Xu, Y'
  'Xu, T'
_journal_name_full                 'Journal of Alloys and Compounds'
_journal_volume                    327
_journal_year                      2001
_journal_page_first                210
_journal_page_last                 214
_cell_length_a                     4.8113(1)
_cell_length_b                     4.8113(1)
_cell_length_c                    15.2781(3)
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                 120
_cell_volume                       306.29
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'P-31c'
_symmetry_Int_Tables_number        163
_symmetry_cell_setting             Hexagonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-y,x-y,z'
  '-x+y,-x,z'
  '-y,-x,1/2-z'
  '-x+y,y,1/2-z'
  'x,x-y,1/2-z'
  '-x,-y,-z'
  'y,y-x,-z'
  'x-y,x,-z'
  'y,x,1/2+z'
  'x-y,-y,1/2+z'
  '-x,y-x,1/2+z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Al3+   3.000
  B3+    3.000
  Na1+   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
  Al    Al3+   4 f  0.3333     0.6667     0.6374(3)  1.  0 d
  B1    B3+    4 f  0.3333     0.6667     0.0978(9)  1.  0 d
  Na1   Na1+   2 b  0.0000     0.0000     0.0000     1.  0 d
  Na2   Na1+   2 a  0.0000     0.0000     0.2500     1.  0 d
  O1    O2-   12 i  0.9704(6)  0.6087(6)  0.8916(3)  1.  0 d
  O2    O2-    2 d  0.6666     0.3333     0.2500     1.  0 d
_refine_ls_R_factor_all            0.06