data_KMnNb2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.26
_cell_length_b   10.26
_cell_length_c   10.26
_cell_angle_alpha   17.44
_cell_angle_beta   17.44
_cell_angle_gamma   17.44
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMnNb2
_chemical_formula_sum   'K1 Mn1 Nb2'
_cell_volume   84.67
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  K  K0  1  0.0  0.0  0.0  1.0
  Mn  Mn1  1  0.0  0.0  0.15  1.0
  Nb  Nb2  1  0.0  0.0  0.5  1.0
  Nb  Nb3  1  0.0  0.0  0.8  1.0

data_KMnNb2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.39
_cell_length_b   3.11
_cell_length_c   10.26
_cell_angle_alpha   90.0
_cell_angle_beta   100.08
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   KMnNb2
_chemical_formula_sum   'K2 Mn2 Nb4'
_cell_volume   169.33
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  K  K0  2  0.0  0.0  0.0  1.0
  Mn  Mn1  2  0.0  0.0  0.85  1.0
  Nb  Nb2  2  0.0  0.0  0.2  1.0
  Nb  Nb3  2  0.0  0.0  0.5  1.0

K Mn Nb Nb
KNb2Mn crystallizes in the monoclinic Cm space group. K(1) is bonded in a linear geometry to one Nb(2) and one Mn(1) atom. The K(1)-Nb(2) bond length is 2.02 Å. The K(1)-Mn(1) bond length is 1.58 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Nb(2), six equivalent Nb(1), and one Mn(1) atom to form a mixture of edge and corner-sharing NbMnNb7 hexagonal bipyramids. The Nb(1)-Nb(2) bond length is 3.07 Å. All Nb(1)-Nb(1) bond lengths are 3.11 Å. The Nb(1)-Mn(1) bond length is 3.59 Å. In the second Nb site, Nb(2) is bonded in a single-bond geometry to one K(1) and one Nb(1) atom. Mn(1) is bonded in a single-bond geometry to one K(1) and one Nb(1) atom.