The compound described by Mg2YbCu9 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to three equivalent Cu(5) and nine equivalent Cu(2) atoms. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to three equivalent Cu(4) and nine equivalent Cu(6) atoms. Yb(1) is bonded in a distorted hexagonal planar geometry to three equivalent Cu(1), three equivalent Cu(3), six equivalent Cu(2), and six equivalent Cu(6) atoms. There are six inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 12-coordinate geometry to three equivalent Yb(1), three equivalent Cu(2), three equivalent Cu(3), and three equivalent Cu(6) atoms. In the second Cu site, Cu(2) is bonded to three equivalent Mg(1), two equivalent Yb(1), one Cu(1), one Cu(3), one Cu(5), and four equivalent Cu(2) atoms to form CuYb2Mg3Cu7 cuboctahedra that share corners with two equivalent Cu(5)Mg6Cu6 cuboctahedra, corners with six equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra, corners with nine equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra,  a faceface with one Cu(6)Yb2Mg3Cu7 cuboctahedra, faces with three equivalent Cu(5)Mg6Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra. In the third Cu site, Cu(3) is bonded in a 12-coordinate geometry to three equivalent Yb(1), three equivalent Cu(1), three equivalent Cu(2), and three equivalent Cu(6) atoms. In the fourth Cu site, Cu(4) is bonded to six equivalent Mg(2) and six equivalent Cu(6) atoms to form CuMg6Cu6 cuboctahedra that share corners with twelve equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra, edges with six equivalent Cu(4)Mg6Cu6 cuboctahedra, and faces with eighteen equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra. In the fifth Cu site, Cu(5) is bonded to six equivalent Mg(1) and six equivalent Cu(2) atoms to form CuMg6Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with six equivalent Cu(5)Mg6Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra. In the sixth Cu site, Cu(6) is bonded to three equivalent Mg(2), two equivalent Yb(1), one Cu(1), one Cu(3), one Cu(4), and four equivalent Cu(6) atoms to form CuYb2Mg3Cu7 cuboctahedra that share corners with two equivalent Cu(4)Mg6Cu6 cuboctahedra, corners with six equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, corners with nine equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra,  a faceface with one Cu(2)Yb2Mg3Cu7 cuboctahedra, faces with three equivalent Cu(4)Mg6Cu6 cuboctahedra, and faces with ten equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra. is represented by the CIF file [CIF]
data_YbMg2Cu9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.924
_cell_length_b   4.924
_cell_length_c   16.007
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   119.993
_symmetry_Int_Tables_number   1
_cell_volume   336.094
_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  0.667  0.333  0.250  1.0
  Yb  Yb1  1  0.333  0.667  0.750  1.0
  Mg  Mg2  1  0.667  0.333  0.468  1.0
  Mg  Mg3  1  0.333  0.667  0.968  1.0
  Mg  Mg4  1  0.667  0.333  0.032  1.0
  Mg  Mg5  1  0.333  0.667  0.532  1.0
  Cu  Cu6  1  0.333  0.667  0.250  1.0
  Cu  Cu7  1  0.667  0.333  0.750  1.0
  Cu  Cu8  1  0.168  0.832  0.376  1.0
  Cu  Cu9  1  0.168  0.336  0.376  1.0
  Cu  Cu10  1  1.000  0.000  0.750  1.0
  Cu  Cu11  1  0.000  1.000  0.250  1.0
  Cu  Cu12  1  0.000  0.000  1.000  1.0
  Cu  Cu13  1  0.000  0.000  0.500  1.0
  Cu  Cu14  1  0.168  0.336  0.124  1.0
  Cu  Cu15  1  0.832  0.168  0.624  1.0
  Cu  Cu16  1  0.336  0.168  0.624  1.0
  Cu  Cu17  1  0.664  0.832  0.124  1.0
  Cu  Cu18  1  0.168  0.832  0.124  1.0
  Cu  Cu19  1  0.832  0.664  0.876  1.0
  Cu  Cu20  1  0.832  0.168  0.876  1.0
  Cu  Cu21  1  0.832  0.664  0.624  1.0
  Cu  Cu22  1  0.336  0.168  0.876  1.0
  Cu  Cu23  1  0.664  0.832  0.376  1.0
[/CIF]
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The compound described by Mg2YbCu9 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to three equivalent Cu(5) and nine equivalent Cu(2) atoms. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to three equivalent Cu(4) and nine equivalent Cu(6) atoms. Yb(1) is bonded in a distorted hexagonal planar geometry to three equivalent Cu(1), three equivalent Cu(3), six equivalent Cu(2), and six equivalent Cu(6) atoms. There are six inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 12-coordinate geometry to three equivalent Yb(1), three equivalent Cu(2), three equivalent Cu(3), and three equivalent Cu(6) atoms. In the second Cu site, Cu(2) is bonded to three equivalent Mg(1), two equivalent Yb(1), one Cu(1), one Cu(3), one Cu(5), and four equivalent Cu(2) atoms to form CuYb2Mg3Cu7 cuboctahedra that share corners with two equivalent Cu(5)Mg6Cu6 cuboctahedra, corners with six equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra, corners with nine equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra,  a faceface with one Cu(6)Yb2Mg3Cu7 cuboctahedra, faces with three equivalent Cu(5)Mg6Cu6 cuboctahedra, and faces with ten equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra. In the third Cu site, Cu(3) is bonded in a 12-coordinate geometry to three equivalent Yb(1), three equivalent Cu(1), three equivalent Cu(2), and three equivalent Cu(6) atoms. In the fourth Cu site, Cu(4) is bonded to six equivalent Mg(2) and six equivalent Cu(6) atoms to form CuMg6Cu6 cuboctahedra that share corners with twelve equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra, edges with six equivalent Cu(4)Mg6Cu6 cuboctahedra, and faces with eighteen equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra. In the fifth Cu site, Cu(5) is bonded to six equivalent Mg(1) and six equivalent Cu(2) atoms to form CuMg6Cu6 cuboctahedra that share corners with twelve equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with six equivalent Cu(5)Mg6Cu6 cuboctahedra, and faces with eighteen equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra. In the sixth Cu site, Cu(6) is bonded to three equivalent Mg(2), two equivalent Yb(1), one Cu(1), one Cu(3), one Cu(4), and four equivalent Cu(6) atoms to form CuYb2Mg3Cu7 cuboctahedra that share corners with two equivalent Cu(4)Mg6Cu6 cuboctahedra, corners with six equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, corners with nine equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(2)Yb2Mg3Cu7 cuboctahedra, edges with four equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra,  a faceface with one Cu(2)Yb2Mg3Cu7 cuboctahedra, faces with three equivalent Cu(4)Mg6Cu6 cuboctahedra, and faces with ten equivalent Cu(6)Yb2Mg3Cu7 cuboctahedra. is represented by the CIF file [CIF]
data_YbMg2Cu9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.924
_cell_length_b   4.924
_cell_length_c   16.007
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   119.993
_symmetry_Int_Tables_number   1
_cell_volume   336.094
_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  0.667  0.333  0.250  1.0
  Yb  Yb1  1  0.333  0.667  0.750  1.0
  Mg  Mg2  1  0.667  0.333  0.468  1.0
  Mg  Mg3  1  0.333  0.667  0.968  1.0
  Mg  Mg4  1  0.667  0.333  0.032  1.0
  Mg  Mg5  1  0.333  0.667  0.532  1.0
  Cu  Cu6  1  0.333  0.667  0.250  1.0
  Cu  Cu7  1  0.667  0.333  0.750  1.0
  Cu  Cu8  1  0.168  0.832  0.376  1.0
  Cu  Cu9  1  0.168  0.336  0.376  1.0
  Cu  Cu10  1  1.000  0.000  0.750  1.0
  Cu  Cu11  1  0.000  1.000  0.250  1.0
  Cu  Cu12  1  0.000  0.000  1.000  1.0
  Cu  Cu13  1  0.000  0.000  0.500  1.0
  Cu  Cu14  1  0.168  0.336  0.124  1.0
  Cu  Cu15  1  0.832  0.168  0.624  1.0
  Cu  Cu16  1  0.336  0.168  0.624  1.0
  Cu  Cu17  1  0.664  0.832  0.124  1.0
  Cu  Cu18  1  0.168  0.832  0.124  1.0
  Cu  Cu19  1  0.832  0.664  0.876  1.0
  Cu  Cu20  1  0.832  0.168  0.876  1.0
  Cu  Cu21  1  0.832  0.664  0.624  1.0
  Cu  Cu22  1  0.336  0.168  0.876  1.0
  Cu  Cu23  1  0.664  0.832  0.376  1.0
[/CIF]
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