The structure described by KMg14Cu crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cu(1) atoms to form KMg10Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent K(1)Mg10Cu2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)K2Mg10 cuboctahedra, edges with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)K2Mg10 cuboctahedra, faces with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, and faces with four equivalent Mg(5)KMg10Cu cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent K(1)Mg10Cu2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)K2Mg10 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Cu(1)K2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent K(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent K(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent Cu(1) atoms to form distorted MgK2Mg8Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Cu(1)K2Mg10 cuboctahedra, edges with four equivalent Mg(5)KMg10Cu cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent K(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Cu(1)K2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)KMg10Cu cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent K(1)Mg10Cu2 cuboctahedra, corners with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, corners with four equivalent Cu(1)K2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)KMg10Cu cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)KMg10Cu cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one K(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one Cu(1) atom to form distorted MgKMg10Cu cuboctahedra that share corners with four equivalent Mg(7)KMg11 cuboctahedra, corners with ten equivalent Mg(5)KMg10Cu cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(5)KMg10Cu cuboctahedra, edges with two equivalent Mg(7)KMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)K2Mg10 cuboctahedra,  a faceface with one K(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cu(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Cu(1) atom. In the seventh Mg site, Mg(7) is bonded to one K(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), and four equivalent Mg(5) atoms to form distorted MgKMg11 cuboctahedra that share corners with six equivalent Mg(7)KMg11 cuboctahedra, corners with eight equivalent Mg(5)KMg10Cu cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(5)KMg10Cu cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one K(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, faces with three equivalent Cu(1)K2Mg10 cuboctahedra, and faces with four equivalent Mg(5)KMg10Cu cuboctahedra. Cu(1) is bonded to two equivalent K(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form CuK2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Cu(1)K2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent K(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. is represented by the CIF file [CIF]
data_KMg14Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.453
_cell_length_b   6.429
_cell_length_c   10.458
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   119.873
_symmetry_Int_Tables_number   1
_cell_volume   376.221
_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  0.167  0.834  0.125  1.0
  Mg  Mg1  1  0.164  0.332  0.625  1.0
  Mg  Mg2  1  0.167  0.834  0.625  1.0
  Mg  Mg3  1  0.664  0.341  0.125  1.0
  Mg  Mg4  1  0.665  0.329  0.625  1.0
  Mg  Mg5  1  0.664  0.823  0.125  1.0
  Mg  Mg6  1  0.665  0.836  0.625  1.0
  Mg  Mg7  1  0.335  0.177  0.382  1.0
  Mg  Mg8  1  0.335  0.177  0.868  1.0
  Mg  Mg9  1  0.335  0.658  0.382  1.0
  Mg  Mg10  1  0.335  0.658  0.868  1.0
  Mg  Mg11  1  0.842  0.171  0.362  1.0
  Mg  Mg12  1  0.842  0.171  0.888  1.0
  Mg  Mg13  1  0.826  0.663  0.390  1.0
  Mg  Mg14  1  0.826  0.663  0.860  1.0
  Cu  Cu15  1  0.167  0.333  0.125  1.0
[/CIF]
.
The structure described by KMg14Cu crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Mg(7), four equivalent Mg(3), four equivalent Mg(5), and two equivalent Cu(1) atoms to form KMg10Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with six equivalent K(1)Mg10Cu2 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)K2Mg10 cuboctahedra, edges with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)K2Mg10 cuboctahedra, faces with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, and faces with four equivalent Mg(5)KMg10Cu cuboctahedra. There are seven inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(2), two equivalent Mg(6), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent K(1)Mg10Cu2 cuboctahedra, corners with six equivalent Mg(1)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Cu(1)K2Mg10 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, faces with four equivalent Mg(4)Mg12 cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(7), four equivalent Mg(4), and four equivalent Mg(5) atoms to form MgMg12 cuboctahedra that share corners with four equivalent Cu(1)K2Mg10 cuboctahedra, corners with six equivalent Mg(2)Mg12 cuboctahedra, corners with eight equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent K(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent K(1), two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and two equivalent Cu(1) atoms to form distorted MgK2Mg8Cu2 cuboctahedra that share corners with four equivalent Mg(1)Mg12 cuboctahedra, corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with four equivalent Mg(4)Mg12 cuboctahedra, corners with six equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Cu(1)K2Mg10 cuboctahedra, edges with four equivalent Mg(5)KMg10Cu cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent K(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with two equivalent Cu(1)K2Mg10 cuboctahedra, and faces with eight equivalent Mg(5)KMg10Cu cuboctahedra. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(6), and two equivalent Mg(7) atoms to form MgMg12 cuboctahedra that share corners with four equivalent K(1)Mg10Cu2 cuboctahedra, corners with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, corners with four equivalent Cu(1)K2Mg10 cuboctahedra, corners with six equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with four equivalent Mg(5)KMg10Cu cuboctahedra, edges with four equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with two equivalent Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, and faces with eight equivalent Mg(5)KMg10Cu cuboctahedra. In the fifth Mg site, Mg(5) is bonded to one K(1), one Mg(1), one Mg(2), one Mg(3), one Mg(4), two equivalent Mg(5), two equivalent Mg(6), two equivalent Mg(7), and one Cu(1) atom to form distorted MgKMg10Cu cuboctahedra that share corners with four equivalent Mg(7)KMg11 cuboctahedra, corners with ten equivalent Mg(5)KMg10Cu cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with two equivalent Mg(5)KMg10Cu cuboctahedra, edges with two equivalent Mg(7)KMg11 cuboctahedra, edges with two equivalent Mg(1)Mg12 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with two equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent Cu(1)K2Mg10 cuboctahedra,  a faceface with one K(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(1)Mg12 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra,  a faceface with one Cu(1)K2Mg10 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, and faces with four equivalent Mg(4)Mg12 cuboctahedra. In the sixth Mg site, Mg(6) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(7), four equivalent Mg(5), and one Cu(1) atom. In the seventh Mg site, Mg(7) is bonded to one K(1), one Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), and four equivalent Mg(5) atoms to form distorted MgKMg11 cuboctahedra that share corners with six equivalent Mg(7)KMg11 cuboctahedra, corners with eight equivalent Mg(5)KMg10Cu cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with two equivalent Mg(2)Mg12 cuboctahedra, edges with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with four equivalent Mg(5)KMg10Cu cuboctahedra, edges with four equivalent Mg(4)Mg12 cuboctahedra,  a faceface with one K(1)Mg10Cu2 cuboctahedra,  a faceface with one Mg(2)Mg12 cuboctahedra, faces with two equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with two equivalent Mg(7)KMg11 cuboctahedra, faces with two equivalent Mg(4)Mg12 cuboctahedra, faces with three equivalent Mg(1)Mg12 cuboctahedra, faces with three equivalent Cu(1)K2Mg10 cuboctahedra, and faces with four equivalent Mg(5)KMg10Cu cuboctahedra. Cu(1) is bonded to two equivalent K(1), two equivalent Mg(6), four equivalent Mg(3), and four equivalent Mg(5) atoms to form CuK2Mg10 cuboctahedra that share corners with four equivalent Mg(2)Mg12 cuboctahedra, corners with six equivalent Cu(1)K2Mg10 cuboctahedra, corners with eight equivalent Mg(4)Mg12 cuboctahedra, edges with two equivalent K(1)Mg10Cu2 cuboctahedra, edges with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, edges with eight equivalent Mg(5)KMg10Cu cuboctahedra, faces with two equivalent K(1)Mg10Cu2 cuboctahedra, faces with two equivalent Mg(1)Mg12 cuboctahedra, faces with four equivalent Mg(3)K2Mg8Cu2 cuboctahedra, faces with four equivalent Mg(5)KMg10Cu cuboctahedra, and faces with six equivalent Mg(7)KMg11 cuboctahedra. is represented by the CIF file [CIF]
data_KMg14Cu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.453
_cell_length_b   6.429
_cell_length_c   10.458
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   119.873
_symmetry_Int_Tables_number   1
_cell_volume   376.221
_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  0.167  0.834  0.125  1.0
  Mg  Mg1  1  0.164  0.332  0.625  1.0
  Mg  Mg2  1  0.167  0.834  0.625  1.0
  Mg  Mg3  1  0.664  0.341  0.125  1.0
  Mg  Mg4  1  0.665  0.329  0.625  1.0
  Mg  Mg5  1  0.664  0.823  0.125  1.0
  Mg  Mg6  1  0.665  0.836  0.625  1.0
  Mg  Mg7  1  0.335  0.177  0.382  1.0
  Mg  Mg8  1  0.335  0.177  0.868  1.0
  Mg  Mg9  1  0.335  0.658  0.382  1.0
  Mg  Mg10  1  0.335  0.658  0.868  1.0
  Mg  Mg11  1  0.842  0.171  0.362  1.0
  Mg  Mg12  1  0.842  0.171  0.888  1.0
  Mg  Mg13  1  0.826  0.663  0.390  1.0
  Mg  Mg14  1  0.826  0.663  0.860  1.0
  Cu  Cu15  1  0.167  0.333  0.125  1.0
[/CIF]
.