The compound described by Er6Al3Si crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent Al(2) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing ErAl5 trigonal bipyramids. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to one Al(1), three equivalent Al(2), one Si(1), and one Si(2) atom. In the third Er site, Er(3) is bonded in a 4-coordinate geometry to two equivalent Al(1) and four equivalent Al(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to two equivalent Er(3), three equivalent Er(1), and four equivalent Er(2) atoms. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Er(1), two equivalent Er(3), six equivalent Er(2), and one Al(2) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a body-centered cubic geometry to eight equivalent Er(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to eight equivalent Er(2) atoms. is represented by the CIF card [CIF]
data_Er6Al3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.096
_cell_length_b   11.096
_cell_length_c   11.096
_cell_angle_alpha   117.853
_cell_angle_beta   117.853
_cell_angle_gamma   93.762
_symmetry_Int_Tables_number   1
_cell_volume   995.173
_cell_formula_units_Z   4
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  0.169  0.669  0.837  1.0
  Er  Er1  1  0.831  0.331  0.163  1.0
  Er  Er2  1  0.669  0.831  0.500  1.0
  Er  Er3  1  0.331  0.169  0.500  1.0
  Er  Er4  1  0.831  0.699  0.261  1.0
  Er  Er5  1  0.169  0.301  0.739  1.0
  Er  Er6  1  0.438  0.570  0.739  1.0
  Er  Er7  1  0.699  0.438  0.868  1.0
  Er  Er8  1  0.062  0.801  0.132  1.0
  Er  Er9  1  0.562  0.430  0.261  1.0
  Er  Er10  1  0.301  0.562  0.132  1.0
  Er  Er11  1  0.938  0.199  0.868  1.0
  Er  Er12  1  0.570  0.831  0.132  1.0
  Er  Er13  1  0.669  0.930  0.868  1.0
  Er  Er14  1  0.430  0.169  0.868  1.0
  Er  Er15  1  0.331  0.070  0.132  1.0
  Er  Er16  1  0.930  0.062  0.261  1.0
  Er  Er17  1  0.070  0.938  0.739  1.0
  Er  Er18  1  0.801  0.669  0.739  1.0
  Er  Er19  1  0.199  0.331  0.261  1.0
  Er  Er20  1  0.147  0.647  0.500  1.0
  Er  Er21  1  0.853  0.353  0.500  1.0
  Er  Er22  1  0.647  0.147  0.500  1.0
  Er  Er23  1  0.353  0.853  0.500  1.0
  Al  Al24  1  0.622  0.122  0.744  1.0
  Al  Al25  1  0.378  0.878  0.256  1.0
  Al  Al26  1  0.122  0.378  0.500  1.0
  Al  Al27  1  0.878  0.622  0.500  1.0
  Al  Al28  1  0.382  0.882  0.854  1.0
  Al  Al29  1  0.618  0.118  0.146  1.0
  Al  Al30  1  0.028  0.528  0.146  1.0
  Al  Al31  1  0.882  0.028  0.500  1.0
  Al  Al32  1  0.472  0.618  0.500  1.0
  Al  Al33  1  0.972  0.472  0.854  1.0
  Al  Al34  1  0.118  0.972  0.500  1.0
  Al  Al35  1  0.528  0.382  0.500  1.0
  Si  Si36  1  0.500  0.500  0.000  1.0
  Si  Si37  1  0.000  0.000  0.000  1.0
  Si  Si38  1  0.750  0.750  0.000  1.0
  Si  Si39  1  0.250  0.250  0.000  1.0
[/CIF]
.
The compound described by Er6Al3Si crystallizes in the tetragonal I4/mcm space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent Al(2) and three equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing ErAl5 trigonal bipyramids. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to one Al(1), three equivalent Al(2), one Si(1), and one Si(2) atom. In the third Er site, Er(3) is bonded in a 4-coordinate geometry to two equivalent Al(1) and four equivalent Al(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a 9-coordinate geometry to two equivalent Er(3), three equivalent Er(1), and four equivalent Er(2) atoms. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Er(1), two equivalent Er(3), six equivalent Er(2), and one Al(2) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a body-centered cubic geometry to eight equivalent Er(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to eight equivalent Er(2) atoms. is represented by the CIF card [CIF]
data_Er6Al3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.096
_cell_length_b   11.096
_cell_length_c   11.096
_cell_angle_alpha   117.853
_cell_angle_beta   117.853
_cell_angle_gamma   93.762
_symmetry_Int_Tables_number   1
_cell_volume   995.173
_cell_formula_units_Z   4
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  0.169  0.669  0.837  1.0
  Er  Er1  1  0.831  0.331  0.163  1.0
  Er  Er2  1  0.669  0.831  0.500  1.0
  Er  Er3  1  0.331  0.169  0.500  1.0
  Er  Er4  1  0.831  0.699  0.261  1.0
  Er  Er5  1  0.169  0.301  0.739  1.0
  Er  Er6  1  0.438  0.570  0.739  1.0
  Er  Er7  1  0.699  0.438  0.868  1.0
  Er  Er8  1  0.062  0.801  0.132  1.0
  Er  Er9  1  0.562  0.430  0.261  1.0
  Er  Er10  1  0.301  0.562  0.132  1.0
  Er  Er11  1  0.938  0.199  0.868  1.0
  Er  Er12  1  0.570  0.831  0.132  1.0
  Er  Er13  1  0.669  0.930  0.868  1.0
  Er  Er14  1  0.430  0.169  0.868  1.0
  Er  Er15  1  0.331  0.070  0.132  1.0
  Er  Er16  1  0.930  0.062  0.261  1.0
  Er  Er17  1  0.070  0.938  0.739  1.0
  Er  Er18  1  0.801  0.669  0.739  1.0
  Er  Er19  1  0.199  0.331  0.261  1.0
  Er  Er20  1  0.147  0.647  0.500  1.0
  Er  Er21  1  0.853  0.353  0.500  1.0
  Er  Er22  1  0.647  0.147  0.500  1.0
  Er  Er23  1  0.353  0.853  0.500  1.0
  Al  Al24  1  0.622  0.122  0.744  1.0
  Al  Al25  1  0.378  0.878  0.256  1.0
  Al  Al26  1  0.122  0.378  0.500  1.0
  Al  Al27  1  0.878  0.622  0.500  1.0
  Al  Al28  1  0.382  0.882  0.854  1.0
  Al  Al29  1  0.618  0.118  0.146  1.0
  Al  Al30  1  0.028  0.528  0.146  1.0
  Al  Al31  1  0.882  0.028  0.500  1.0
  Al  Al32  1  0.472  0.618  0.500  1.0
  Al  Al33  1  0.972  0.472  0.854  1.0
  Al  Al34  1  0.118  0.972  0.500  1.0
  Al  Al35  1  0.528  0.382  0.500  1.0
  Si  Si36  1  0.500  0.500  0.000  1.0
  Si  Si37  1  0.000  0.000  0.000  1.0
  Si  Si38  1  0.750  0.750  0.000  1.0
  Si  Si39  1  0.250  0.250  0.000  1.0
[/CIF]
.