The crystal structure described by KMg6Nb crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form KMg12 cuboctahedra that share corners with four equivalent K(1)Mg12 cuboctahedra, corners with eight equivalent Nb(1)Mg12 cuboctahedra, edges with eight equivalent Mg(1)K2Mg8Nb2 cuboctahedra, faces with two equivalent K(1)Mg12 cuboctahedra, faces with four equivalent Mg(1)K2Mg8Nb2 cuboctahedra, and faces with four equivalent Nb(1)Mg12 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent K(1), two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(2), and two equivalent Nb(1) atoms to form distorted MgK2Mg8Nb2 cuboctahedra that share corners with twelve equivalent Mg(1)K2Mg8Nb2 cuboctahedra, edges with four equivalent K(1)Mg12 cuboctahedra, edges with four equivalent Nb(1)Mg12 cuboctahedra, faces with two equivalent K(1)Mg12 cuboctahedra, faces with two equivalent Nb(1)Mg12 cuboctahedra, and faces with six equivalent Mg(1)K2Mg8Nb2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent K(1), one Mg(3), one Mg(4), four equivalent Mg(1), and two equivalent Nb(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent K(1), two equivalent Mg(2), four equivalent Mg(1), and two equivalent Nb(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent K(1), two equivalent Mg(2), four equivalent Mg(1), and two equivalent Nb(1) atoms. Nb(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form NbMg12 cuboctahedra that share corners with four equivalent Nb(1)Mg12 cuboctahedra, corners with eight equivalent K(1)Mg12 cuboctahedra, edges with eight equivalent Mg(1)K2Mg8Nb2 cuboctahedra, faces with two equivalent Nb(1)Mg12 cuboctahedra, faces with four equivalent K(1)Mg12 cuboctahedra, and faces with four equivalent Mg(1)K2Mg8Nb2 cuboctahedra. is represented by the CIF file [CIF]
data_KMg6Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.557
_cell_length_b   6.557
_cell_length_c   4.581
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.457
_symmetry_Int_Tables_number   1
_cell_volume   196.935
_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  0.870  0.130  0.500  1.0
  Mg  Mg1  1  0.371  0.119  0.500  1.0
  Mg  Mg2  1  0.881  0.629  0.500  1.0
  Mg  Mg3  1  0.157  0.405  0.000  1.0
  Mg  Mg4  1  0.595  0.843  0.000  1.0
  Mg  Mg5  1  0.595  0.405  0.000  1.0
  Mg  Mg6  1  0.154  0.846  0.000  1.0
  Nb  Nb7  1  0.376  0.624  0.500  1.0
[/CIF]
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The crystal structure described by KMg6Nb crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form KMg12 cuboctahedra that share corners with four equivalent K(1)Mg12 cuboctahedra, corners with eight equivalent Nb(1)Mg12 cuboctahedra, edges with eight equivalent Mg(1)K2Mg8Nb2 cuboctahedra, faces with two equivalent K(1)Mg12 cuboctahedra, faces with four equivalent Mg(1)K2Mg8Nb2 cuboctahedra, and faces with four equivalent Nb(1)Mg12 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent K(1), two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(2), and two equivalent Nb(1) atoms to form distorted MgK2Mg8Nb2 cuboctahedra that share corners with twelve equivalent Mg(1)K2Mg8Nb2 cuboctahedra, edges with four equivalent K(1)Mg12 cuboctahedra, edges with four equivalent Nb(1)Mg12 cuboctahedra, faces with two equivalent K(1)Mg12 cuboctahedra, faces with two equivalent Nb(1)Mg12 cuboctahedra, and faces with six equivalent Mg(1)K2Mg8Nb2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to two equivalent K(1), one Mg(3), one Mg(4), four equivalent Mg(1), and two equivalent Nb(1) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to two equivalent K(1), two equivalent Mg(2), four equivalent Mg(1), and two equivalent Nb(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent K(1), two equivalent Mg(2), four equivalent Mg(1), and two equivalent Nb(1) atoms. Nb(1) is bonded to two equivalent Mg(3), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(2) atoms to form NbMg12 cuboctahedra that share corners with four equivalent Nb(1)Mg12 cuboctahedra, corners with eight equivalent K(1)Mg12 cuboctahedra, edges with eight equivalent Mg(1)K2Mg8Nb2 cuboctahedra, faces with two equivalent Nb(1)Mg12 cuboctahedra, faces with four equivalent K(1)Mg12 cuboctahedra, and faces with four equivalent Mg(1)K2Mg8Nb2 cuboctahedra. is represented by the CIF file [CIF]
data_KMg6Nb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.557
_cell_length_b   6.557
_cell_length_c   4.581
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.457
_symmetry_Int_Tables_number   1
_cell_volume   196.935
_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  0.870  0.130  0.500  1.0
  Mg  Mg1  1  0.371  0.119  0.500  1.0
  Mg  Mg2  1  0.881  0.629  0.500  1.0
  Mg  Mg3  1  0.157  0.405  0.000  1.0
  Mg  Mg4  1  0.595  0.843  0.000  1.0
  Mg  Mg5  1  0.595  0.405  0.000  1.0
  Mg  Mg6  1  0.154  0.846  0.000  1.0
  Nb  Nb7  1  0.376  0.624  0.500  1.0
[/CIF]
.