data_1001278
_chemical_name_systematic
;
TRISTRONTIUM TETRATITANIUM TETRANIOBIUM OXIDE
;
_chemical_formula_structural       'SR3 NB4 TI4 O21'
_chemical_formula_sum              'Nb4 O21 Sr3 Ti4'
_publ_section_title
;
Etude du comportement de l'antimoine V et du strontium dans les oxydes
a structure en cages du type A~3~ M~8~ O~21~
;
loop_
_publ_author_name
  'Saurel, C'
  'Groult, D'
  'Raveau, B'
_journal_name_full                 'Materials Research Bulletin'
_journal_coden_ASTM                MRBUAC
_journal_volume                    12
_journal_year                      1977
_journal_page_first                629
_journal_page_last                 635
_cell_length_a                     8.992
_cell_length_b                     8.992
_cell_length_c                     11.605
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  120
_cell_volume                       812.6
_cell_formula_units_Z              2
_symmetry_space_group_name_H-M     'P 63/m c m'
_symmetry_Int_Tables_number        193
_symmetry_cell_setting             hexagonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-y,x-y,z'
  'y-x,-x,z'
  'y,x,z'
  'x-y,-y,z'
  '-x,y-x,z'
  '-x,-y,-z'
  'y,y-x,-z'
  'x-y,x,-z'
  '-y,-x,-z'
  'y-x,y,-z'
  'x,x-y,-z'
  '-x,-y,1/2+z'
  'y,y-x,1/2+z'
  'x-y,x,1/2+z'
  '-y,-x,1/2+z'
  'y-x,y,1/2+z'
  'x,x-y,1/2+z'
  'x,y,1/2-z'
  '-y,x-y,1/2-z'
  'y-x,-x,1/2-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
  Sr2+   2.000
  Ti4+   4.000
  Nb5+   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
  Sr1   Sr2+   6 g 0.595(1) 0. 0.25 1.  0 d
  Ti1   Ti4+  12 k 0.244(1) 0. 0.0929(6) 0.5  0 d
  Nb1   Nb5+  12 k 0.244(1) 0. 0.0929(6) 0.5  0 d
  Nb2   Nb5+   4 d 0.3333 0.6667 0. 0.5  0 d
  Ti2   Ti4+   4 d 0.3333 0.6667 0. 0.5  0 d
  O1    O2-    6 g 0.247(3) 0. 0.25 1.  0 d
  O2    O2-   12 k 0.797(3) 0. 0.078(3) 1.  0 d
  O3    O2-   24 l 0.170(8) 0.500(3) 0.112(2) 1.  0 d
_refine_ls_R_factor_all            0.05