data_global
_amcsd_formula_title 'K3 Nb8 O21'
loop_
_publ_author_name
'Groult D'
'Chailleux J'
'Choisnet J'
'Raveau B'
_journal_name_full 'Journal of Solid State Chemistry'
_journal_volume 19 
_journal_year 1976
_journal_page_first 235
_journal_page_last 244
_publ_section_title
;
 Sur une nouvelle famille d'oxydes ternaires de niobium, A3 M8 O21
 a structure en cages
 _cod_database_code 1001027
;
_database_code_amcsd 0013335
_chemical_formula_sum 'K3 Nb8 O21'
_cell_length_a 9.153
_cell_length_b 9.153
_cell_length_c 12.066
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 875.429
_exptl_crystal_density_diffrn      4.539
_symmetry_space_group_name_H-M 'P 63/m c m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-x+y,z'
  'x,x-y,-z'
  '-x+y,-x,1/2-z'
  'x-y,x,1/2+z'
  '-y,-x,1/2+z'
  'y,x,1/2-z'
  'y,-x+y,-z'
  '-y,x-y,z'
  'x-y,-y,z'
  '-x+y,y,-z'
  'x,y,1/2-z'
  '-x,-y,1/2+z'
  'x,x-y,1/2+z'
  '-x,-x+y,1/2-z'
  'x-y,x,-z'
  '-x+y,-x,z'
  'y,x,z'
  '-y,-x,-z'
  '-y,x-y,1/2-z'
  'y,-x+y,1/2+z'
  '-x+y,y,1/2+z'
  'x-y,-y,1/2-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
K1   0.59800   0.00000   0.25000
Nb1   0.24800   0.00000   0.09900
Nb2   0.33333   0.66667   0.00000
O1   0.22600   0.00000   0.25000
O2   0.79200   0.00000   0.08300
O3   0.17700   0.49400   0.10200