data_KMgNb2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.56
_cell_length_b   6.56
_cell_length_c   5.54
_cell_angle_alpha   107.39
_cell_angle_beta   107.39
_cell_angle_gamma   23.97
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMgNb2
_chemical_formula_sum   'K1 Mg1 Nb2'
_cell_volume   92.12
_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  0.57  0.0  0.64  1.0
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Nb  Nb2  1  0.25  0.0  0.08  1.0
  Nb  Nb3  1  0.89  0.0  0.19  1.0

data_KMgNb2
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.72
_cell_length_b   5.54
_cell_length_c   6.56
_cell_angle_alpha   107.39
_cell_angle_beta   101.98
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMgNb2
_chemical_formula_sum   'K1 Mg1 Nb2'
_cell_volume   92.12
_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  0.64  0.57  1.0
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Nb  Nb2  1  0.0  0.08  0.25  1.0
  Nb  Nb3  1  0.0  0.19  0.89  1.0

K Mg Nb Nb
KMgNb2 crystallizes in the triclinic P1 space group. K(1) is bonded to two equivalent K(1), one Mg(1), two equivalent Nb(1), and two equivalent Nb(2) atoms to form a mixture of distorted corner and edge-sharing KK2MgNb4 pentagonal bipyramids. Both K(1)-K(1) bond lengths are 2.72 Å. The K(1)-Mg(1) bond length is 2.94 Å. There is one shorter (3.15 Å) and one longer (3.68 Å) K(1)-Nb(1) bond length. There is one shorter (3.15 Å) and one longer (3.68 Å) K(1)-Nb(2) bond length. Mg(1) is bonded in a distorted bent 120 degrees geometry to one K(1), one Nb(1), and one Nb(2) atom. The Mg(1)-Nb(1) bond length is 1.56 Å. The Mg(1)-Nb(2) bond length is 1.47 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Mg(1) atom. In the second Nb site, Nb(2) is bonded in a single-bond geometry to two equivalent K(1) and one Mg(1) atom.