The material described by Al4Cu2Mg8Si7 crystallizes in the monoclinic Pm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Si(4), one Si(5), and two equivalent Si(2) atoms to form distorted MgSi4 tetrahedra that share  a cornercorner with one Mg(2)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra, and corners with two equivalent Mg(1)Si4 tetrahedra. In the second Mg site, Mg(2) is bonded to one Si(4), one Si(6), and two equivalent Si(3) atoms to form distorted MgSi4 tetrahedra that share  a cornercorner with one Mg(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra, and corners with two equivalent Mg(2)Si4 tetrahedra. In the third Mg site, Mg(3) is bonded in a 7-coordinate geometry to two equivalent Cu(2), one Si(1), two equivalent Si(5), and two equivalent Si(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to two equivalent Cu(2), one Si(2), two equivalent Si(5), and two equivalent Si(6) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to two equivalent Cu(2), one Si(3), two equivalent Si(6), and two equivalent Si(7) atoms. In the sixth Mg site, Mg(6) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(4), and two equivalent Si(5) atoms. In the seventh Mg site, Mg(7) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(4), and two equivalent Si(6) atoms. In the eighth Mg site, Mg(8) is bonded in a 5-coordinate geometry to one Si(2), two equivalent Si(4), and two equivalent Si(7) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 9-coordinate geometry to two equivalent Al(1), two equivalent Al(2), two equivalent Al(3), one Si(1), one Si(2), and one Si(3) atom. In the second Cu site, Cu(2) is bonded in a 9-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), one Si(5), one Si(6), and one Si(7) atom. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 5-coordinate geometry to two equivalent Cu(1), one Si(5), and two equivalent Si(3) atoms. In the second Al site, Al(2) is bonded in a 7-coordinate geometry to two equivalent Cu(1), one Si(6), two equivalent Si(1), and two equivalent Si(2) atoms. In the third Al site, Al(3) is bonded in a 7-coordinate geometry to two equivalent Cu(1), one Si(7), two equivalent Si(2), and two equivalent Si(3) atoms. In the fourth Al site, Al(4) is bonded to one Si(4), one Si(7), and two equivalent Si(1) atoms to form distorted AlSi4 tetrahedra that share  a cornercorner with one Mg(1)Si4 tetrahedra,  a cornercorner with one Mg(2)Si4 tetrahedra, and corners with two equivalent Al(4)Si4 tetrahedra. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Mg(3), one Mg(7), one Cu(1), two equivalent Al(2), and two equivalent Al(4) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(4), one Mg(8), two equivalent Mg(1), one Cu(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(5), one Mg(6), two equivalent Mg(2), one Cu(1), two equivalent Al(1), and two equivalent Al(3) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), two equivalent Mg(6), two equivalent Mg(7), two equivalent Mg(8), and one Al(4) atom. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), one Cu(2), and one Al(1) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(7), one Cu(2), and one Al(2) atom. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(8), one Cu(2), one Al(3), and one Al(4) atom. is represented by the CIF card [CIF]
data_Mg8Al4Cu2Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.980
_cell_length_b   10.414
_cell_length_c   10.469
_cell_angle_alpha   60.535
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   377.739
_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  0.000  0.253  0.749  1.0
  Mg  Mg1  1  0.000  0.750  0.999  1.0
  Mg  Mg2  1  0.500  0.141  0.378  1.0
  Mg  Mg3  1  0.500  0.380  0.481  1.0
  Mg  Mg4  1  0.500  0.476  0.141  1.0
  Mg  Mg5  1  0.500  0.001  0.797  1.0
  Mg  Mg6  1  0.500  0.796  0.200  1.0
  Mg  Mg7  1  0.500  0.202  0.004  1.0
  Al  Al8  1  0.000  0.849  0.657  1.0
  Al  Al9  1  0.000  0.631  0.512  1.0
  Al  Al10  1  0.000  0.495  0.864  1.0
  Al  Al11  1  0.000  0.002  0.246  1.0
  Cu  Cu12  1  0.500  0.686  0.646  1.0
  Cu  Cu13  1  0.000  0.332  0.336  1.0
  Si  Si14  1  0.500  0.875  0.406  1.0
  Si  Si15  1  0.500  0.437  0.712  1.0
  Si  Si16  1  0.500  0.704  0.859  1.0
  Si  Si17  1  0.000  0.004  0.003  1.0
  Si  Si18  1  0.000  0.125  0.579  1.0
  Si  Si19  1  0.000  0.577  0.295  1.0
  Si  Si20  1  0.000  0.283  0.137  1.0
[/CIF]
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The material described by Al4Cu2Mg8Si7 crystallizes in the monoclinic Pm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Si(4), one Si(5), and two equivalent Si(2) atoms to form distorted MgSi4 tetrahedra that share  a cornercorner with one Mg(2)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra, and corners with two equivalent Mg(1)Si4 tetrahedra. In the second Mg site, Mg(2) is bonded to one Si(4), one Si(6), and two equivalent Si(3) atoms to form distorted MgSi4 tetrahedra that share  a cornercorner with one Mg(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra, and corners with two equivalent Mg(2)Si4 tetrahedra. In the third Mg site, Mg(3) is bonded in a 7-coordinate geometry to two equivalent Cu(2), one Si(1), two equivalent Si(5), and two equivalent Si(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to two equivalent Cu(2), one Si(2), two equivalent Si(5), and two equivalent Si(6) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to two equivalent Cu(2), one Si(3), two equivalent Si(6), and two equivalent Si(7) atoms. In the sixth Mg site, Mg(6) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(4), and two equivalent Si(5) atoms. In the seventh Mg site, Mg(7) is bonded in a 5-coordinate geometry to one Si(1), two equivalent Si(4), and two equivalent Si(6) atoms. In the eighth Mg site, Mg(8) is bonded in a 5-coordinate geometry to one Si(2), two equivalent Si(4), and two equivalent Si(7) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 9-coordinate geometry to two equivalent Al(1), two equivalent Al(2), two equivalent Al(3), one Si(1), one Si(2), and one Si(3) atom. In the second Cu site, Cu(2) is bonded in a 9-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(5), one Si(5), one Si(6), and one Si(7) atom. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded in a 5-coordinate geometry to two equivalent Cu(1), one Si(5), and two equivalent Si(3) atoms. In the second Al site, Al(2) is bonded in a 7-coordinate geometry to two equivalent Cu(1), one Si(6), two equivalent Si(1), and two equivalent Si(2) atoms. In the third Al site, Al(3) is bonded in a 7-coordinate geometry to two equivalent Cu(1), one Si(7), two equivalent Si(2), and two equivalent Si(3) atoms. In the fourth Al site, Al(4) is bonded to one Si(4), one Si(7), and two equivalent Si(1) atoms to form distorted AlSi4 tetrahedra that share  a cornercorner with one Mg(1)Si4 tetrahedra,  a cornercorner with one Mg(2)Si4 tetrahedra, and corners with two equivalent Al(4)Si4 tetrahedra. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Mg(3), one Mg(7), one Cu(1), two equivalent Al(2), and two equivalent Al(4) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(4), one Mg(8), two equivalent Mg(1), one Cu(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(5), one Mg(6), two equivalent Mg(2), one Cu(1), two equivalent Al(1), and two equivalent Al(3) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), two equivalent Mg(6), two equivalent Mg(7), two equivalent Mg(8), and one Al(4) atom. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(3), two equivalent Mg(4), two equivalent Mg(6), one Cu(2), and one Al(1) atom. In the sixth Si site, Si(6) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(4), two equivalent Mg(5), two equivalent Mg(7), one Cu(2), and one Al(2) atom. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to two equivalent Mg(3), two equivalent Mg(5), two equivalent Mg(8), one Cu(2), one Al(3), and one Al(4) atom. is represented by the CIF card [CIF]
data_Mg8Al4Cu2Si7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.980
_cell_length_b   10.414
_cell_length_c   10.469
_cell_angle_alpha   60.535
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   377.739
_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  0.000  0.253  0.749  1.0
  Mg  Mg1  1  0.000  0.750  0.999  1.0
  Mg  Mg2  1  0.500  0.141  0.378  1.0
  Mg  Mg3  1  0.500  0.380  0.481  1.0
  Mg  Mg4  1  0.500  0.476  0.141  1.0
  Mg  Mg5  1  0.500  0.001  0.797  1.0
  Mg  Mg6  1  0.500  0.796  0.200  1.0
  Mg  Mg7  1  0.500  0.202  0.004  1.0
  Al  Al8  1  0.000  0.849  0.657  1.0
  Al  Al9  1  0.000  0.631  0.512  1.0
  Al  Al10  1  0.000  0.495  0.864  1.0
  Al  Al11  1  0.000  0.002  0.246  1.0
  Cu  Cu12  1  0.500  0.686  0.646  1.0
  Cu  Cu13  1  0.000  0.332  0.336  1.0
  Si  Si14  1  0.500  0.875  0.406  1.0
  Si  Si15  1  0.500  0.437  0.712  1.0
  Si  Si16  1  0.500  0.704  0.859  1.0
  Si  Si17  1  0.000  0.004  0.003  1.0
  Si  Si18  1  0.000  0.125  0.579  1.0
  Si  Si19  1  0.000  0.577  0.295  1.0
  Si  Si20  1  0.000  0.283  0.137  1.0
[/CIF]
.