data_1001529
_chemical_name_systematic          'Phosphorus nonaniobium oxide'
_chemical_formula_structural       'P Nb9 O25'
_chemical_formula_sum              'Nb9 O25 P'
_publ_section_title
;
Redetermination of the structure of PNb~9~O~25~
;
loop_
_publ_author_name
  'Benabbas, A'
  'Borel, M M'
  'Grandin, A'
  'Leclaire, A'
  'Raveau, B'
_journal_name_full                 'Acta Crystallographica C (39,1983-)'
_journal_coden_ASTM                ACSCEE
_journal_volume                    47
_journal_year                      1991
_journal_page_first                849
_journal_page_last                 850
_cell_length_a                     15.639(2)
_cell_length_b                     15.639(2)
_cell_length_c                     3.8317(4)
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  90
_cell_volume                       937.2
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'I 4/m'
_symmetry_Int_Tables_number        87
_symmetry_cell_setting             tetragonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-x,-y,z'
  '-y,x,z'
  'y,-x,z'
  '-x,-y,-z'
  'x,y,-z'
  'y,-x,-z'
  '-y,x,-z'
  '1/2+x,1/2+y,1/2+z'
  '1/2-x,1/2-y,1/2+z'
  '1/2-y,1/2+x,1/2+z'
  '1/2+y,1/2-x,1/2+z'
  '1/2-x,1/2-y,1/2-z'
  '1/2+x,1/2+y,1/2-z'
  '1/2+y,1/2-x,1/2-z'
  '1/2-y,1/2+x,1/2-z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Nb5+   5.000
  P5+    5.000
  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
  Nb1   Nb5+   4 e 0. 0. 0.043(1) 0.5  0 d
  Nb2   Nb5+   8 h 0.1086(1) 0.2178(1) 0. 1.  0 d
  Nb3   Nb5+   8 h 0.3291(1) 0.1158(1) 0. 1.  0 d
  P1    P5+    4 d 0.5 0. 0.25 0.5  0 d
  O1    O2-    8 h 0.0461(9) 0.115(1) 0. 1.  0 d
  O2    O2-    8 h 0.2204(9) 0.1733(9) 0. 1.  0 d
  O3    O2-    8 h 0.1557(8) 0.3553(8) 0. 1.  0 d
  O4    O2-    8 h 0.2852(8) 0.0112(8) 0. 1.  0 d
  O5    O2-    8 h 0.4491(8) 0.0685(8) 0. 1.  0 d
  O6    O2-    8 h 0.3872(8) 0.2469(8) 0. 1.  0 d
  O7    O2-    2 b 0. 0. 0.5 1.  0 d
_refine_ls_R_factor_all            0.033