data_1001302
_chemical_name_systematic
;
Hexapotassium hexaniobium tetragermanium oxide
;
_chemical_formula_structural       'K6 Nb6 Ge4 O26'
_chemical_formula_sum              'Ge4 K6 Nb6 O26'
_publ_section_title
;
Etude du comportement du germanium dans les structures a tunnels de
section pentagonale: Les silicogermanates K~6~ Nb~6~ Ge~x~ Si~4-x~
O~26~
;
loop_
_publ_author_name
  'Choisnet, J'
  'Nguyen, N'
  'Raveau, B'
_journal_name_full                 'Revue de Chimie Minerale'
_journal_coden_ASTM                RVCMA8
_journal_volume                    14
_journal_year                      1977
_journal_page_first                311
_journal_page_last                 317
_cell_length_a                     9.188
_cell_length_b                     9.188
_cell_length_c                     8.123
_cell_angle_alpha                  90
_cell_angle_beta                   90
_cell_angle_gamma                  120
_cell_volume                       593.9
_cell_formula_units_Z              1
_symmetry_space_group_name_H-M     'P -6 2 m'
_symmetry_Int_Tables_number        189
_symmetry_cell_setting             hexagonal
loop_
_symmetry_equiv_pos_as_xyz
  'x,y,z'
  '-y,x-y,z'
  'y-x,-x,z'
  'x,y,-z'
  '-y,x-y,-z'
  'y-x,-x,-z'
  'y,x,z'
  'x-y,-y,z'
  '-x,y-x,z'
  'y,x,-z'
  'x-y,-y,-z'
  '-x,y-x,-z'
loop_
_atom_type_symbol
_atom_type_oxidation_number
  K1+    1.000
  Ge4+   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
  K1    K1+    3 g 0.610(5) 0. 0.5 1.  0 d
  K2    K1+    3 f 0.599(6) 0. 0. 1.  0 d
  Ge1   Ge4+   4 h 0.33333 0.66667 0.219(2) 1.  0 d
  Nb1   Nb5+   6 i 0.232(1) 0. 0.239(2) 1.  0 d
  O1    O2-    2 c 0.33333 0.66667 0. 1.  0 d
  O2    O2-    3 f 0.228(14) 0. 0. 1.  0 d
  O3    O2-    6 i 0.831(6) 0. 0.292(13) 1.  0 d
  O4    O2-   12 l 0.478(6) 0.166(6) 0.280(6) 1.  0 d
  O5    O2-    3 g 0.256(9) 0. 0.5 1.  0 d
_refine_ls_R_factor_all            0.088