The compound described by Mg3Yb7Si8 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic P2_1 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(6), and two equivalent Si(7) atoms. In the second Mg site, Mg(2) is bonded in a distorted T-shaped geometry to one Si(2) and two equivalent Si(8) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to one Si(3), one Si(4), one Si(6), one Si(7), and two equivalent Si(1) atoms. There are seven inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 7-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(8) atoms. In the second Yb site, Yb(2) is bonded in a 7-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(7) atoms. In the third Yb site, Yb(3) is bonded in a 7-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(7) atoms. In the fourth Yb site, Yb(4) is bonded in a 6-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and two equivalent Si(8) atoms. In the fifth Yb site, Yb(5) is bonded in a 6-coordinate geometry to one Si(3), one Si(4), one Si(5), one Si(8), and two equivalent Si(2) atoms. In the sixth Yb site, Yb(6) is bonded in a 6-coordinate geometry to one Si(4), one Si(5), one Si(6), one Si(8), and two equivalent Si(2) atoms. In the seventh Yb site, Yb(7) is bonded in a 6-coordinate geometry to one Si(3), one Si(5), one Si(6), one Si(7), and two equivalent Si(1) atoms. There are eight inequivalent Si sites. In the first Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(3), two equivalent Mg(1), one Yb(7), two equivalent Yb(2), two equivalent Yb(3), and one Si(1) atom. In the second Si site, Si(8) is bonded in a 9-coordinate geometry to two equivalent Mg(2), one Yb(5), one Yb(6), two equivalent Yb(1), two equivalent Yb(4), and one Si(2) atom. In the third Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(3), one Yb(2), one Yb(3), two equivalent Yb(7), and one Si(7) atom. In the fourth Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), one Yb(1), one Yb(4), two equivalent Yb(5), two equivalent Yb(6), and one Si(8) atom. In the fifth Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), one Yb(1), one Yb(2), one Yb(3), one Yb(4), one Yb(5), one Yb(7), and one Si(5) atom. In the sixth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(3), one Yb(1), one Yb(2), one Yb(3), one Yb(4), one Yb(5), one Yb(6), and one Si(6) atom. In the seventh Si site, Si(5) is bonded in a 8-coordinate geometry to one Yb(1), one Yb(2), one Yb(3), one Yb(4), one Yb(5), one Yb(6), one Yb(7), and one Si(3) atom. In the eighth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), one Yb(1), one Yb(2), one Yb(3), one Yb(6), one Yb(7), and one Si(4) atom. is represented by the CIF file [CIF]
data_Yb7Mg3Si8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.104
_cell_length_b   7.746
_cell_length_c   15.078
_cell_angle_alpha   89.473
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   829.686
_cell_formula_units_Z   2
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
  Yb  Yb0  1  0.514  0.569  0.342  1.0
  Yb  Yb1  1  0.014  0.431  0.658  1.0
  Yb  Yb2  1  0.485  0.930  0.848  1.0
  Yb  Yb3  1  0.985  0.070  0.152  1.0
  Yb  Yb4  1  0.486  0.921  0.151  1.0
  Yb  Yb5  1  0.986  0.079  0.849  1.0
  Yb  Yb6  1  0.517  0.567  0.653  1.0
  Yb  Yb7  1  0.017  0.433  0.347  1.0
  Yb  Yb8  1  0.176  0.935  0.376  1.0
  Yb  Yb9  1  0.676  0.065  0.624  1.0
  Yb  Yb10  1  0.175  0.930  0.626  1.0
  Yb  Yb11  1  0.675  0.070  0.374  1.0
  Yb  Yb12  1  0.830  0.562  0.123  1.0
  Yb  Yb13  1  0.330  0.438  0.877  1.0
  Mg  Mg14  1  0.652  0.230  0.000  1.0
  Mg  Mg15  1  0.152  0.770  1.000  1.0
  Mg  Mg16  1  0.348  0.279  0.503  1.0
  Mg  Mg17  1  0.848  0.721  0.497  1.0
  Mg  Mg18  1  0.821  0.562  0.878  1.0
  Mg  Mg19  1  0.321  0.438  0.122  1.0
  Si  Si20  1  0.534  0.659  0.996  1.0
  Si  Si21  1  0.034  0.341  0.004  1.0
  Si  Si22  1  0.477  0.832  0.499  1.0
  Si  Si23  1  0.977  0.168  0.501  1.0
  Si  Si24  1  0.659  0.281  0.786  1.0
  Si  Si25  1  0.159  0.719  0.214  1.0
  Si  Si26  1  0.339  0.227  0.272  1.0
  Si  Si27  1  0.839  0.773  0.728  1.0
  Si  Si28  1  0.357  0.222  0.721  1.0
  Si  Si29  1  0.857  0.778  0.279  1.0
  Si  Si30  1  0.632  0.273  0.206  1.0
  Si  Si31  1  0.132  0.727  0.794  1.0
  Si  Si32  1  0.770  0.873  0.001  1.0
  Si  Si33  1  0.270  0.127  0.999  1.0
  Si  Si34  1  0.229  0.623  0.501  1.0
  Si  Si35  1  0.729  0.377  0.499  1.0
[/CIF]
.
The compound described by Mg3Yb7Si8 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic P2_1 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(6), and two equivalent Si(7) atoms. In the second Mg site, Mg(2) is bonded in a distorted T-shaped geometry to one Si(2) and two equivalent Si(8) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to one Si(3), one Si(4), one Si(6), one Si(7), and two equivalent Si(1) atoms. There are seven inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 7-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(8) atoms. In the second Yb site, Yb(2) is bonded in a 7-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(7) atoms. In the third Yb site, Yb(3) is bonded in a 7-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(7) atoms. In the fourth Yb site, Yb(4) is bonded in a 6-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and two equivalent Si(8) atoms. In the fifth Yb site, Yb(5) is bonded in a 6-coordinate geometry to one Si(3), one Si(4), one Si(5), one Si(8), and two equivalent Si(2) atoms. In the sixth Yb site, Yb(6) is bonded in a 6-coordinate geometry to one Si(4), one Si(5), one Si(6), one Si(8), and two equivalent Si(2) atoms. In the seventh Yb site, Yb(7) is bonded in a 6-coordinate geometry to one Si(3), one Si(5), one Si(6), one Si(7), and two equivalent Si(1) atoms. There are eight inequivalent Si sites. In the first Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(3), two equivalent Mg(1), one Yb(7), two equivalent Yb(2), two equivalent Yb(3), and one Si(1) atom. In the second Si site, Si(8) is bonded in a 9-coordinate geometry to two equivalent Mg(2), one Yb(5), one Yb(6), two equivalent Yb(1), two equivalent Yb(4), and one Si(2) atom. In the third Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Mg(3), one Yb(2), one Yb(3), two equivalent Yb(7), and one Si(7) atom. In the fourth Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), one Yb(1), one Yb(4), two equivalent Yb(5), two equivalent Yb(6), and one Si(8) atom. In the fifth Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(3), one Yb(1), one Yb(2), one Yb(3), one Yb(4), one Yb(5), one Yb(7), and one Si(5) atom. In the sixth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(3), one Yb(1), one Yb(2), one Yb(3), one Yb(4), one Yb(5), one Yb(6), and one Si(6) atom. In the seventh Si site, Si(5) is bonded in a 8-coordinate geometry to one Yb(1), one Yb(2), one Yb(3), one Yb(4), one Yb(5), one Yb(6), one Yb(7), and one Si(3) atom. In the eighth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), one Yb(1), one Yb(2), one Yb(3), one Yb(6), one Yb(7), and one Si(4) atom. is represented by the CIF file [CIF]
data_Yb7Mg3Si8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.104
_cell_length_b   7.746
_cell_length_c   15.078
_cell_angle_alpha   89.473
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   829.686
_cell_formula_units_Z   2
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
  Yb  Yb0  1  0.514  0.569  0.342  1.0
  Yb  Yb1  1  0.014  0.431  0.658  1.0
  Yb  Yb2  1  0.485  0.930  0.848  1.0
  Yb  Yb3  1  0.985  0.070  0.152  1.0
  Yb  Yb4  1  0.486  0.921  0.151  1.0
  Yb  Yb5  1  0.986  0.079  0.849  1.0
  Yb  Yb6  1  0.517  0.567  0.653  1.0
  Yb  Yb7  1  0.017  0.433  0.347  1.0
  Yb  Yb8  1  0.176  0.935  0.376  1.0
  Yb  Yb9  1  0.676  0.065  0.624  1.0
  Yb  Yb10  1  0.175  0.930  0.626  1.0
  Yb  Yb11  1  0.675  0.070  0.374  1.0
  Yb  Yb12  1  0.830  0.562  0.123  1.0
  Yb  Yb13  1  0.330  0.438  0.877  1.0
  Mg  Mg14  1  0.652  0.230  0.000  1.0
  Mg  Mg15  1  0.152  0.770  1.000  1.0
  Mg  Mg16  1  0.348  0.279  0.503  1.0
  Mg  Mg17  1  0.848  0.721  0.497  1.0
  Mg  Mg18  1  0.821  0.562  0.878  1.0
  Mg  Mg19  1  0.321  0.438  0.122  1.0
  Si  Si20  1  0.534  0.659  0.996  1.0
  Si  Si21  1  0.034  0.341  0.004  1.0
  Si  Si22  1  0.477  0.832  0.499  1.0
  Si  Si23  1  0.977  0.168  0.501  1.0
  Si  Si24  1  0.659  0.281  0.786  1.0
  Si  Si25  1  0.159  0.719  0.214  1.0
  Si  Si26  1  0.339  0.227  0.272  1.0
  Si  Si27  1  0.839  0.773  0.728  1.0
  Si  Si28  1  0.357  0.222  0.721  1.0
  Si  Si29  1  0.857  0.778  0.279  1.0
  Si  Si30  1  0.632  0.273  0.206  1.0
  Si  Si31  1  0.132  0.727  0.794  1.0
  Si  Si32  1  0.770  0.873  0.001  1.0
  Si  Si33  1  0.270  0.127  0.999  1.0
  Si  Si34  1  0.229  0.623  0.501  1.0
  Si  Si35  1  0.729  0.377  0.499  1.0
[/CIF]
.