The structure described by Al2Er11Ge8 crystallizes in the tetragonal I4/mmm space group. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to four equivalent Al(1), one Ge(2), and four equivalent Ge(4) atoms. In the second Er site, Er(2) is bonded to one Al(1), two equivalent Ge(2), two equivalent Ge(3), and two equivalent Ge(4) atoms to form distorted ErAlGe6 pentagonal bipyramids that share corners with eight equivalent Er(3)Ge7 pentagonal bipyramids,  an edgeedge with one Er(2)AlGe6 pentagonal bipyramid, faces with two equivalent Er(2)AlGe6 pentagonal bipyramids, and faces with four equivalent Er(3)Ge7 pentagonal bipyramids. In the third Er site, Er(3) is bonded to one Ge(1), one Ge(2), one Ge(3), and four equivalent Ge(4) atoms to form distorted ErGe7 pentagonal bipyramids that share corners with three equivalent Er(3)Ge7 pentagonal bipyramids, corners with four equivalent Er(2)AlGe6 pentagonal bipyramids, edges with two equivalent Er(3)Ge7 pentagonal bipyramids, faces with two equivalent Er(2)AlGe6 pentagonal bipyramids, and faces with four equivalent Er(3)Ge7 pentagonal bipyramids. In the fourth Er site, Er(4) is bonded in a 7-coordinate geometry to two equivalent Al(1), one Ge(1), two equivalent Ge(3), and two equivalent Ge(4) atoms. Al(1) is bonded in a 11-coordinate geometry to one Er(2), two equivalent Er(1), four equivalent Er(4), two equivalent Al(1), and two equivalent Ge(4) atoms. There are four inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to four equivalent Er(3) and four equivalent Er(4) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to one Er(1), four equivalent Er(2), and four equivalent Er(3) atoms. In the third Ge site, Ge(3) is bonded in a 8-coordinate geometry to two equivalent Er(2), two equivalent Er(3), and four equivalent Er(4) atoms. In the fourth Ge site, Ge(4) is bonded in a 10-coordinate geometry to one Er(1), one Er(2), two equivalent Er(4), four equivalent Er(3), one Al(1), and one Ge(4) atom. is represented by the CIF card [CIF]
data_Er11(AlGe4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.187
_cell_length_b   11.187
_cell_length_c   11.187
_cell_angle_alpha   121.399
_cell_angle_beta   121.399
_cell_angle_gamma   87.594
_symmetry_Int_Tables_number   1
_cell_volume   968.211
_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  0.665  0.665  0.000  1.0
  Er  Er1  1  0.335  0.335  0.000  1.0
  Er  Er2  1  0.176  0.176  0.352  1.0
  Er  Er3  1  0.824  0.824  0.648  1.0
  Er  Er4  1  0.176  0.824  0.000  1.0
  Er  Er5  1  0.824  0.176  0.000  1.0
  Er  Er6  1  0.810  0.062  0.252  1.0
  Er  Er7  1  0.810  0.558  0.748  1.0
  Er  Er8  1  0.062  0.810  0.252  1.0
  Er  Er9  1  0.558  0.810  0.748  1.0
  Er  Er10  1  0.190  0.938  0.748  1.0
  Er  Er11  1  0.190  0.442  0.252  1.0
  Er  Er12  1  0.938  0.190  0.748  1.0
  Er  Er13  1  0.442  0.190  0.252  1.0
  Er  Er14  1  0.602  0.932  0.330  1.0
  Er  Er15  1  0.602  0.272  0.670  1.0
  Er  Er16  1  0.932  0.602  0.330  1.0
  Er  Er17  1  0.272  0.602  0.670  1.0
  Er  Er18  1  0.398  0.068  0.670  1.0
  Er  Er19  1  0.398  0.728  0.330  1.0
  Er  Er20  1  0.068  0.398  0.670  1.0
  Er  Er21  1  0.728  0.398  0.330  1.0
  Al  Al22  1  0.378  0.378  0.757  1.0
  Al  Al23  1  0.622  0.622  0.243  1.0
  Al  Al24  1  0.378  0.622  0.000  1.0
  Al  Al25  1  0.622  0.378  0.000  1.0
  Ge  Ge26  1  0.750  0.250  0.500  1.0
  Ge  Ge27  1  0.250  0.750  0.500  1.0
  Ge  Ge28  1  0.882  0.882  0.000  1.0
  Ge  Ge29  1  0.118  0.118  0.000  1.0
  Ge  Ge30  1  0.356  0.000  0.356  1.0
  Ge  Ge31  1  0.644  0.000  0.644  1.0
  Ge  Ge32  1  0.000  0.644  0.644  1.0
  Ge  Ge33  1  0.000  0.356  0.356  1.0
  Ge  Ge34  1  0.882  0.882  0.412  1.0
  Ge  Ge35  1  0.470  0.470  0.588  1.0
  Ge  Ge36  1  0.882  0.470  0.000  1.0
  Ge  Ge37  1  0.470  0.882  0.000  1.0
  Ge  Ge38  1  0.118  0.118  0.588  1.0
  Ge  Ge39  1  0.530  0.530  0.412  1.0
  Ge  Ge40  1  0.118  0.530  0.000  1.0
  Ge  Ge41  1  0.530  0.118  0.000  1.0
[/CIF]
.
The structure described by Al2Er11Ge8 crystallizes in the tetragonal I4/mmm space group. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to four equivalent Al(1), one Ge(2), and four equivalent Ge(4) atoms. In the second Er site, Er(2) is bonded to one Al(1), two equivalent Ge(2), two equivalent Ge(3), and two equivalent Ge(4) atoms to form distorted ErAlGe6 pentagonal bipyramids that share corners with eight equivalent Er(3)Ge7 pentagonal bipyramids,  an edgeedge with one Er(2)AlGe6 pentagonal bipyramid, faces with two equivalent Er(2)AlGe6 pentagonal bipyramids, and faces with four equivalent Er(3)Ge7 pentagonal bipyramids. In the third Er site, Er(3) is bonded to one Ge(1), one Ge(2), one Ge(3), and four equivalent Ge(4) atoms to form distorted ErGe7 pentagonal bipyramids that share corners with three equivalent Er(3)Ge7 pentagonal bipyramids, corners with four equivalent Er(2)AlGe6 pentagonal bipyramids, edges with two equivalent Er(3)Ge7 pentagonal bipyramids, faces with two equivalent Er(2)AlGe6 pentagonal bipyramids, and faces with four equivalent Er(3)Ge7 pentagonal bipyramids. In the fourth Er site, Er(4) is bonded in a 7-coordinate geometry to two equivalent Al(1), one Ge(1), two equivalent Ge(3), and two equivalent Ge(4) atoms. Al(1) is bonded in a 11-coordinate geometry to one Er(2), two equivalent Er(1), four equivalent Er(4), two equivalent Al(1), and two equivalent Ge(4) atoms. There are four inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 8-coordinate geometry to four equivalent Er(3) and four equivalent Er(4) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to one Er(1), four equivalent Er(2), and four equivalent Er(3) atoms. In the third Ge site, Ge(3) is bonded in a 8-coordinate geometry to two equivalent Er(2), two equivalent Er(3), and four equivalent Er(4) atoms. In the fourth Ge site, Ge(4) is bonded in a 10-coordinate geometry to one Er(1), one Er(2), two equivalent Er(4), four equivalent Er(3), one Al(1), and one Ge(4) atom. is represented by the CIF card [CIF]
data_Er11(AlGe4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.187
_cell_length_b   11.187
_cell_length_c   11.187
_cell_angle_alpha   121.399
_cell_angle_beta   121.399
_cell_angle_gamma   87.594
_symmetry_Int_Tables_number   1
_cell_volume   968.211
_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  0.665  0.665  0.000  1.0
  Er  Er1  1  0.335  0.335  0.000  1.0
  Er  Er2  1  0.176  0.176  0.352  1.0
  Er  Er3  1  0.824  0.824  0.648  1.0
  Er  Er4  1  0.176  0.824  0.000  1.0
  Er  Er5  1  0.824  0.176  0.000  1.0
  Er  Er6  1  0.810  0.062  0.252  1.0
  Er  Er7  1  0.810  0.558  0.748  1.0
  Er  Er8  1  0.062  0.810  0.252  1.0
  Er  Er9  1  0.558  0.810  0.748  1.0
  Er  Er10  1  0.190  0.938  0.748  1.0
  Er  Er11  1  0.190  0.442  0.252  1.0
  Er  Er12  1  0.938  0.190  0.748  1.0
  Er  Er13  1  0.442  0.190  0.252  1.0
  Er  Er14  1  0.602  0.932  0.330  1.0
  Er  Er15  1  0.602  0.272  0.670  1.0
  Er  Er16  1  0.932  0.602  0.330  1.0
  Er  Er17  1  0.272  0.602  0.670  1.0
  Er  Er18  1  0.398  0.068  0.670  1.0
  Er  Er19  1  0.398  0.728  0.330  1.0
  Er  Er20  1  0.068  0.398  0.670  1.0
  Er  Er21  1  0.728  0.398  0.330  1.0
  Al  Al22  1  0.378  0.378  0.757  1.0
  Al  Al23  1  0.622  0.622  0.243  1.0
  Al  Al24  1  0.378  0.622  0.000  1.0
  Al  Al25  1  0.622  0.378  0.000  1.0
  Ge  Ge26  1  0.750  0.250  0.500  1.0
  Ge  Ge27  1  0.250  0.750  0.500  1.0
  Ge  Ge28  1  0.882  0.882  0.000  1.0
  Ge  Ge29  1  0.118  0.118  0.000  1.0
  Ge  Ge30  1  0.356  0.000  0.356  1.0
  Ge  Ge31  1  0.644  0.000  0.644  1.0
  Ge  Ge32  1  0.000  0.644  0.644  1.0
  Ge  Ge33  1  0.000  0.356  0.356  1.0
  Ge  Ge34  1  0.882  0.882  0.412  1.0
  Ge  Ge35  1  0.470  0.470  0.588  1.0
  Ge  Ge36  1  0.882  0.470  0.000  1.0
  Ge  Ge37  1  0.470  0.882  0.000  1.0
  Ge  Ge38  1  0.118  0.118  0.588  1.0
  Ge  Ge39  1  0.530  0.530  0.412  1.0
  Ge  Ge40  1  0.118  0.530  0.000  1.0
  Ge  Ge41  1  0.530  0.118  0.000  1.0
[/CIF]
.