The material structure described by Er5(Co2Si7)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 18-coordinate geometry to two equivalent Co(2), four equivalent Co(1), two equivalent Si(3), two equivalent Si(4), two equivalent Si(5), two equivalent Si(6), and four equivalent Si(1) atoms. In the second Er site, Er(2) is bonded to two equivalent Co(2), one Si(3), one Si(4), two equivalent Si(5), three equivalent Si(2), and three equivalent Si(7) atoms to form a mixture of distorted edge, corner, and face-sharing ErCo2Si10 cuboctahedra. In the third Er site, Er(3) is bonded to two equivalent Co(2), one Si(3), one Si(4), two equivalent Si(6), three equivalent Si(2), and three equivalent Si(7) atoms to form a mixture of distorted edge, corner, and face-sharing ErCo2Si10 cuboctahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 10-coordinate geometry to two equivalent Er(1), one Co(1), one Si(3), one Si(4), one Si(5), one Si(6), and three equivalent Si(1) atoms. In the second Co site, Co(2) is bonded in a 10-coordinate geometry to one Er(1), two equivalent Er(2), two equivalent Er(3), one Si(3), one Si(4), one Si(5), one Si(6), and one Si(7) atom. There are seven inequivalent Si sites. In the first Si site, Si(5) is bonded in a 8-coordinate geometry to one Er(1), two equivalent Er(2), one Co(1), one Co(2), one Si(1), one Si(3), and one Si(4) atom. In the second Si site, Si(6) is bonded in a 8-coordinate geometry to one Er(1), two equivalent Er(3), one Co(1), one Co(2), one Si(1), one Si(3), and one Si(4) atom. In the third Si site, Si(7) is bonded in a 9-coordinate geometry to three equivalent Er(2), three equivalent Er(3), one Co(2), one Si(2), and one Si(7) atom. In the fourth Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Er(1), three equivalent Co(1), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the fifth Si site, Si(2) is bonded in a 8-coordinate geometry to three equivalent Er(2), three equivalent Er(3), one Si(2), and one Si(7) atom. In the sixth Si site, Si(3) is bonded in a 8-coordinate geometry to one Er(1), one Er(2), one Er(3), one Co(1), one Co(2), one Si(1), one Si(5), and one Si(6) atom. In the seventh Si site, Si(4) is bonded in a 8-coordinate geometry to one Er(1), one Er(2), one Er(3), one Co(1), one Co(2), one Si(1), one Si(5), and one Si(6) atom. is represented by the CIF card [CIF]
data_Er5(Co2Si7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.757
_cell_length_b   7.682
_cell_length_c   12.336
_cell_angle_alpha   81.296
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   726.651
_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
  Er  Er0  1  0.000  0.000  0.500  1.0
  Er  Er1  1  0.500  0.500  0.500  1.0
  Er  Er2  1  0.252  0.158  0.863  1.0
  Er  Er3  1  0.752  0.342  0.137  1.0
  Er  Er4  1  0.748  0.842  0.137  1.0
  Er  Er5  1  0.248  0.658  0.863  1.0
  Er  Er6  1  0.249  0.839  0.136  1.0
  Er  Er7  1  0.749  0.661  0.864  1.0
  Er  Er8  1  0.751  0.161  0.864  1.0
  Er  Er9  1  0.251  0.339  0.136  1.0
  Co  Co10  1  0.372  0.871  0.500  1.0
  Co  Co11  1  0.872  0.629  0.500  1.0
  Co  Co12  1  0.628  0.129  0.500  1.0
  Co  Co13  1  0.128  0.371  0.500  1.0
  Co  Co14  1  1.000  0.940  0.748  1.0
  Co  Co15  1  0.500  0.560  0.252  1.0
  Co  Co16  1  0.000  0.060  0.252  1.0
  Co  Co17  1  0.500  0.440  0.748  1.0
  Si  Si18  1  0.664  0.837  0.500  1.0
  Si  Si19  1  0.164  0.663  0.500  1.0
  Si  Si20  1  0.336  0.163  0.500  1.0
  Si  Si21  1  0.836  0.337  0.500  1.0
  Si  Si22  1  0.500  0.886  0.944  1.0
  Si  Si23  1  1.000  0.614  0.056  1.0
  Si  Si24  1  0.500  0.114  0.056  1.0
  Si  Si25  1  0.000  0.386  0.944  1.0
  Si  Si26  1  0.994  0.768  0.324  1.0
  Si  Si27  1  0.494  0.732  0.676  1.0
  Si  Si28  1  0.006  0.232  0.676  1.0
  Si  Si29  1  0.506  0.268  0.324  1.0
  Si  Si30  1  0.994  0.682  0.677  1.0
  Si  Si31  1  0.494  0.818  0.323  1.0
  Si  Si32  1  0.006  0.318  0.323  1.0
  Si  Si33  1  0.506  0.182  0.677  1.0
  Si  Si34  1  0.274  0.950  0.676  1.0
  Si  Si35  1  0.774  0.550  0.324  1.0
  Si  Si36  1  0.726  0.050  0.324  1.0
  Si  Si37  1  0.226  0.450  0.676  1.0
  Si  Si38  1  0.726  0.963  0.676  1.0
  Si  Si39  1  0.226  0.537  0.324  1.0
  Si  Si40  1  0.274  0.037  0.324  1.0
  Si  Si41  1  0.774  0.463  0.676  1.0
  Si  Si42  1  0.000  0.892  0.939  1.0
  Si  Si43  1  0.500  0.608  0.061  1.0
  Si  Si44  1  1.000  0.108  0.061  1.0
  Si  Si45  1  0.500  0.392  0.939  1.0
[/CIF]
.
The material structure described by Er5(Co2Si7)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 18-coordinate geometry to two equivalent Co(2), four equivalent Co(1), two equivalent Si(3), two equivalent Si(4), two equivalent Si(5), two equivalent Si(6), and four equivalent Si(1) atoms. In the second Er site, Er(2) is bonded to two equivalent Co(2), one Si(3), one Si(4), two equivalent Si(5), three equivalent Si(2), and three equivalent Si(7) atoms to form a mixture of distorted edge, corner, and face-sharing ErCo2Si10 cuboctahedra. In the third Er site, Er(3) is bonded to two equivalent Co(2), one Si(3), one Si(4), two equivalent Si(6), three equivalent Si(2), and three equivalent Si(7) atoms to form a mixture of distorted edge, corner, and face-sharing ErCo2Si10 cuboctahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 10-coordinate geometry to two equivalent Er(1), one Co(1), one Si(3), one Si(4), one Si(5), one Si(6), and three equivalent Si(1) atoms. In the second Co site, Co(2) is bonded in a 10-coordinate geometry to one Er(1), two equivalent Er(2), two equivalent Er(3), one Si(3), one Si(4), one Si(5), one Si(6), and one Si(7) atom. There are seven inequivalent Si sites. In the first Si site, Si(5) is bonded in a 8-coordinate geometry to one Er(1), two equivalent Er(2), one Co(1), one Co(2), one Si(1), one Si(3), and one Si(4) atom. In the second Si site, Si(6) is bonded in a 8-coordinate geometry to one Er(1), two equivalent Er(3), one Co(1), one Co(2), one Si(1), one Si(3), and one Si(4) atom. In the third Si site, Si(7) is bonded in a 9-coordinate geometry to three equivalent Er(2), three equivalent Er(3), one Co(2), one Si(2), and one Si(7) atom. In the fourth Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Er(1), three equivalent Co(1), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the fifth Si site, Si(2) is bonded in a 8-coordinate geometry to three equivalent Er(2), three equivalent Er(3), one Si(2), and one Si(7) atom. In the sixth Si site, Si(3) is bonded in a 8-coordinate geometry to one Er(1), one Er(2), one Er(3), one Co(1), one Co(2), one Si(1), one Si(5), and one Si(6) atom. In the seventh Si site, Si(4) is bonded in a 8-coordinate geometry to one Er(1), one Er(2), one Er(3), one Co(1), one Co(2), one Si(1), one Si(5), and one Si(6) atom. is represented by the CIF card [CIF]
data_Er5(Co2Si7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.757
_cell_length_b   7.682
_cell_length_c   12.336
_cell_angle_alpha   81.296
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   726.651
_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
  Er  Er0  1  0.000  0.000  0.500  1.0
  Er  Er1  1  0.500  0.500  0.500  1.0
  Er  Er2  1  0.252  0.158  0.863  1.0
  Er  Er3  1  0.752  0.342  0.137  1.0
  Er  Er4  1  0.748  0.842  0.137  1.0
  Er  Er5  1  0.248  0.658  0.863  1.0
  Er  Er6  1  0.249  0.839  0.136  1.0
  Er  Er7  1  0.749  0.661  0.864  1.0
  Er  Er8  1  0.751  0.161  0.864  1.0
  Er  Er9  1  0.251  0.339  0.136  1.0
  Co  Co10  1  0.372  0.871  0.500  1.0
  Co  Co11  1  0.872  0.629  0.500  1.0
  Co  Co12  1  0.628  0.129  0.500  1.0
  Co  Co13  1  0.128  0.371  0.500  1.0
  Co  Co14  1  1.000  0.940  0.748  1.0
  Co  Co15  1  0.500  0.560  0.252  1.0
  Co  Co16  1  0.000  0.060  0.252  1.0
  Co  Co17  1  0.500  0.440  0.748  1.0
  Si  Si18  1  0.664  0.837  0.500  1.0
  Si  Si19  1  0.164  0.663  0.500  1.0
  Si  Si20  1  0.336  0.163  0.500  1.0
  Si  Si21  1  0.836  0.337  0.500  1.0
  Si  Si22  1  0.500  0.886  0.944  1.0
  Si  Si23  1  1.000  0.614  0.056  1.0
  Si  Si24  1  0.500  0.114  0.056  1.0
  Si  Si25  1  0.000  0.386  0.944  1.0
  Si  Si26  1  0.994  0.768  0.324  1.0
  Si  Si27  1  0.494  0.732  0.676  1.0
  Si  Si28  1  0.006  0.232  0.676  1.0
  Si  Si29  1  0.506  0.268  0.324  1.0
  Si  Si30  1  0.994  0.682  0.677  1.0
  Si  Si31  1  0.494  0.818  0.323  1.0
  Si  Si32  1  0.006  0.318  0.323  1.0
  Si  Si33  1  0.506  0.182  0.677  1.0
  Si  Si34  1  0.274  0.950  0.676  1.0
  Si  Si35  1  0.774  0.550  0.324  1.0
  Si  Si36  1  0.726  0.050  0.324  1.0
  Si  Si37  1  0.226  0.450  0.676  1.0
  Si  Si38  1  0.726  0.963  0.676  1.0
  Si  Si39  1  0.226  0.537  0.324  1.0
  Si  Si40  1  0.274  0.037  0.324  1.0
  Si  Si41  1  0.774  0.463  0.676  1.0
  Si  Si42  1  0.000  0.892  0.939  1.0
  Si  Si43  1  0.500  0.608  0.061  1.0
  Si  Si44  1  1.000  0.108  0.061  1.0
  Si  Si45  1  0.500  0.392  0.939  1.0
[/CIF]
.