data_1001834
_chemical_name_systematic
;
Niobium tungsten oxide phosphate(V) (0.79/0.21/1/1) $-alpha-$-alpha'
;
_chemical_formula_structural       '(Nb0.787 W0.213) O (P O4)'
_chemical_formula_sum              'Nb.787 O5 P W.213'
_publ_section_title
;
Combination of $-alpha-Nb O P O4 type layers with enantiomorphic $-
alpha'-type layers: the "racemic structure" of $-alpha-$-alpha'-
(Nb0.787 W0.213 O P O4)
;
loop_
_publ_author_name
  'Leclaire, A'
  'Borel, M M'
  'Raveau, B'
  'Mezaoui, D'
_journal_name_full
;
Zeitschrift fuer Kristallographie (149,1979-)
;
_journal_coden_ASTM                ZEKRDZ
_journal_volume                    212
_journal_year                      1997
_journal_page_first                837
_journal_page_last                 839
_cell_length_a                     6.3524(7)
_cell_length_b                     6.3524(7)
_cell_length_c                     4.0916(5)
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  90
_cell_volume                       165.1
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'P 4/n m m Z'
_symmetry_Int_Tables_number        129
_symmetry_cell_setting             tetragonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '1/2-x,y,z'
  'x,1/2-y,z'
  '1/2-x,1/2-y,z'
  'y,x,z'
  '1/2-y,x,z'
  'y,1/2-x,z'
  '1/2-y,1/2-x,z'
  '-x,-y,-z'
  '1/2+x,-y,-z'
  '-x,1/2+y,-z'
  '1/2+x,1/2+y,-z'
  '-y,-x,-z'
  '1/2+y,-x,-z'
  '-y,1/2+x,-z'
  '1/2+y,1/2+x,-z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  Nb5+   5.000
  W5+    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+   2 c 0.25 0.25 0.28336(9) 0.787(6)  0 d
  W1    W5+    2 c 0.25 0.25 0.28336(9) 0.213(6)  0 d
  P1    P5+    2 a 0.25 0.75 0. 1.  0 d
  O1    O2-    2 c 0.25 0.25 0.710(1) 1.  0 d
  O2    O2-   16 k 0.2154(4) 0.5569(4) 0.2137(5) 0.5  0 d
_refine_ls_R_factor_all            0.024