The material structure described by Mg6CuSi crystallizes in the orthorhombic Amm2 space group. There are nine inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra. In the second Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3)Mg8Cu2Si2 cuboctahedra. In the third Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(1,1,1,1); four Mg(3,3); and two equivalent Cu(1) atoms to form distorted MgMg10Cu2 cuboctahedra that share corners with four equivalent Cu(1)Mg10 cuboctahedra; corners with six equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with eight Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; edges with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Si(1)Mg10 cuboctahedra. In the fourth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with ten Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with three equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four equivalent Mg(1)Mg8Cu2Si2 cuboctahedra;  a faceface with one Si(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(1,1,1)Mg8Cu2Si2 cuboctahedra. In the fifth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with ten Mg(3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with three equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four equivalent Mg(1)Mg8Cu2Si2 cuboctahedra;  a faceface with one Si(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(1,1,1)Mg8Cu2Si2 cuboctahedra. In the sixth Mg site, Mg(4) is bonded to two equivalent Mg(2); four Mg(1,1); four Mg(3,3,3); and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with four equivalent Si(1)Mg10 cuboctahedra; corners with six equivalent Mg(4)Mg10Si2 cuboctahedra; corners with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; edges with eight Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; faces with four Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Cu(1)Mg10 cuboctahedra. In the seventh Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3)Mg8Cu2Si2 cuboctahedra. In the eighth Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra. In the ninth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with ten Mg(3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with three equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four equivalent Mg(1)Mg8Cu2Si2 cuboctahedra;  a faceface with one Si(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(1,1,1)Mg8Cu2Si2 cuboctahedra. Cu(1) is bonded to two equivalent Mg(2); four Mg(1,1,1,1); and four Mg(3,3) atoms to form distorted CuMg10 cuboctahedra that share corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; corners with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; corners with six equivalent Cu(1)Mg10 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; edges with four equivalent Si(1)Mg10 cuboctahedra; edges with six Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two Mg(1,1)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Mg(4)Mg10Si2 cuboctahedra. Si(1) is bonded to two equivalent Mg(4); four Mg(1,1); and four Mg(3,3,3) atoms to form distorted SiMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; corners with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; corners with six equivalent Si(1)Mg10 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; edges with four equivalent Cu(1)Mg10 cuboctahedra; edges with six Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two Mg(3,3)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Mg(2)Mg10Cu2 cuboctahedra. is represented by the CIF card [CIF]
data_Mg6CuSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.056
_cell_length_b   6.056
_cell_length_c   4.955
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.338
_symmetry_Int_Tables_number   1
_cell_volume   156.850
_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
  Mg  Mg0  1  0.167  0.341  0.000  1.0
  Mg  Mg1  1  0.659  0.833  0.000  1.0
  Mg  Mg2  1  0.667  0.333  0.000  1.0
  Mg  Mg3  1  0.330  0.151  0.500  1.0
  Mg  Mg4  1  0.849  0.670  0.500  1.0
  Mg  Mg5  1  0.833  0.167  0.500  1.0
  Cu  Cu6  1  0.164  0.836  0.000  1.0
  Si  Si7  1  0.333  0.667  0.500  1.0
[/CIF]
.
The material structure described by Mg6CuSi crystallizes in the orthorhombic Amm2 space group. There are nine inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra. In the second Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3)Mg8Cu2Si2 cuboctahedra. In the third Mg site, Mg(2) is bonded to two equivalent Mg(4); four Mg(1,1,1,1); four Mg(3,3); and two equivalent Cu(1) atoms to form distorted MgMg10Cu2 cuboctahedra that share corners with four equivalent Cu(1)Mg10 cuboctahedra; corners with six equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with eight Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; edges with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Si(1)Mg10 cuboctahedra. In the fourth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with ten Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with three equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four equivalent Mg(1)Mg8Cu2Si2 cuboctahedra;  a faceface with one Si(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(1,1,1)Mg8Cu2Si2 cuboctahedra. In the fifth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with ten Mg(3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with three equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four equivalent Mg(1)Mg8Cu2Si2 cuboctahedra;  a faceface with one Si(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(1,1,1)Mg8Cu2Si2 cuboctahedra. In the sixth Mg site, Mg(4) is bonded to two equivalent Mg(2); four Mg(1,1); four Mg(3,3,3); and two equivalent Si(1) atoms to form distorted MgMg10Si2 cuboctahedra that share corners with four equivalent Si(1)Mg10 cuboctahedra; corners with six equivalent Mg(4)Mg10Si2 cuboctahedra; corners with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; edges with eight Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; faces with four Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Cu(1)Mg10 cuboctahedra. In the seventh Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3)Mg8Cu2Si2 cuboctahedra. In the eighth Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with ten Mg(1,1,1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Mg(1)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with three equivalent Cu(1)Mg10 cuboctahedra; edges with four equivalent Mg(4)Mg10Si2 cuboctahedra; edges with four equivalent Mg(3)Mg8Cu2Si2 cuboctahedra;  a faceface with one Cu(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(3,3,3)Mg8Cu2Si2 cuboctahedra. In the ninth Mg site, Mg(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Cu(1), and two equivalent Si(1) atoms to form distorted MgMg8Cu2Si2 cuboctahedra that share corners with two equivalent Cu(1)Mg10 cuboctahedra; corners with two equivalent Si(1)Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with ten Mg(3,3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Mg(3)Mg8Cu2Si2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with three equivalent Si(1)Mg10 cuboctahedra; edges with four equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with four equivalent Mg(1)Mg8Cu2Si2 cuboctahedra;  a faceface with one Si(1)Mg10 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with eight Mg(1,1,1)Mg8Cu2Si2 cuboctahedra. Cu(1) is bonded to two equivalent Mg(2); four Mg(1,1,1,1); and four Mg(3,3) atoms to form distorted CuMg10 cuboctahedra that share corners with four equivalent Mg(2)Mg10Cu2 cuboctahedra; corners with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; corners with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; corners with six equivalent Cu(1)Mg10 cuboctahedra; edges with two equivalent Mg(2)Mg10Cu2 cuboctahedra; edges with two equivalent Cu(1)Mg10 cuboctahedra; edges with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; edges with four equivalent Si(1)Mg10 cuboctahedra; edges with six Mg(1,1,1,1)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(2)Mg10Cu2 cuboctahedra; faces with two Mg(1,1)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Si(1)Mg10 cuboctahedra; faces with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Mg(4)Mg10Si2 cuboctahedra. Si(1) is bonded to two equivalent Mg(4); four Mg(1,1); and four Mg(3,3,3) atoms to form distorted SiMg10 cuboctahedra that share corners with four equivalent Mg(4)Mg10Si2 cuboctahedra; corners with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; corners with four Mg(3,3)Mg8Cu2Si2 cuboctahedra; corners with six equivalent Si(1)Mg10 cuboctahedra; edges with two equivalent Mg(4)Mg10Si2 cuboctahedra; edges with two equivalent Si(1)Mg10 cuboctahedra; edges with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; edges with four equivalent Cu(1)Mg10 cuboctahedra; edges with six Mg(3,3,3)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Mg(4)Mg10Si2 cuboctahedra; faces with two Mg(3,3)Mg8Cu2Si2 cuboctahedra; faces with two equivalent Cu(1)Mg10 cuboctahedra; faces with four Mg(1,1)Mg8Cu2Si2 cuboctahedra; and faces with six equivalent Mg(2)Mg10Cu2 cuboctahedra. is represented by the CIF card [CIF]
data_Mg6CuSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.056
_cell_length_b   6.056
_cell_length_c   4.955
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.338
_symmetry_Int_Tables_number   1
_cell_volume   156.850
_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
  Mg  Mg0  1  0.167  0.341  0.000  1.0
  Mg  Mg1  1  0.659  0.833  0.000  1.0
  Mg  Mg2  1  0.667  0.333  0.000  1.0
  Mg  Mg3  1  0.330  0.151  0.500  1.0
  Mg  Mg4  1  0.849  0.670  0.500  1.0
  Mg  Mg5  1  0.833  0.167  0.500  1.0
  Cu  Cu6  1  0.164  0.836  0.000  1.0
  Si  Si7  1  0.333  0.667  0.500  1.0
[/CIF]
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