The material described by Er(CrAl)6 crystallizes in the orthorhombic Immm space group. Er(1) is bonded to four equivalent Cr(2), eight equivalent Cr(1), two equivalent Al(1), two equivalent Al(2), and four equivalent Al(3) atoms to form distorted ErAl8Cr12 hexagonal bipyramids that share corners with eight equivalent Er(1)Al8Cr12 hexagonal bipyramids, faces with eight equivalent Cr(2)Er2Al6Cr4 cuboctahedra, faces with sixteen equivalent Cr(1)Er2Al6Cr4 cuboctahedra, and faces with two equivalent Er(1)Al8Cr12 hexagonal bipyramids. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Er(1), two equivalent Cr(1), two equivalent Cr(2), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms to form distorted CrEr2Al6Cr4 cuboctahedra that share corners with four equivalent Cr(2)Er2Al6Cr4 cuboctahedra, corners with ten equivalent Cr(1)Er2Al6Cr4 cuboctahedra, edges with two equivalent Cr(2)Er2Al6Cr4 cuboctahedra, edges with four equivalent Cr(1)Er2Al6Cr4 cuboctahedra, faces with four equivalent Cr(2)Er2Al6Cr4 cuboctahedra, faces with six equivalent Cr(1)Er2Al6Cr4 cuboctahedra, and faces with four equivalent Er(1)Al8Cr12 hexagonal bipyramids. In the second Cr site, Cr(2) is bonded to two equivalent Er(1), four equivalent Cr(1), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms to form distorted CrEr2Al6Cr4 cuboctahedra that share corners with six equivalent Cr(2)Er2Al6Cr4 cuboctahedra, corners with eight equivalent Cr(1)Er2Al6Cr4 cuboctahedra, edges with three equivalent Cr(2)Er2Al6Cr4 cuboctahedra, edges with four equivalent Cr(1)Er2Al6Cr4 cuboctahedra,  a faceface with one Cr(2)Er2Al6Cr4 cuboctahedra, faces with eight equivalent Cr(1)Er2Al6Cr4 cuboctahedra, and faces with four equivalent Er(1)Al8Cr12 hexagonal bipyramids. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to one Er(1), two equivalent Cr(2), four equivalent Cr(1), one Al(1), and two equivalent Al(3) atoms. In the second Al site, Al(2) is bonded in a 7-coordinate geometry to one Er(1), two equivalent Cr(2), four equivalent Cr(1), and two equivalent Al(3) atoms. In the third Al site, Al(3) is bonded in a 12-coordinate geometry to two equivalent Er(1), two equivalent Cr(2), four equivalent Cr(1), two equivalent Al(1), and two equivalent Al(2) atoms. is represented by the CIF card [CIF]
data_Er(AlCr)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.064
_cell_length_b   6.670
_cell_length_c   6.670
_cell_angle_alpha   97.476
_cell_angle_beta   112.308
_cell_angle_gamma   67.692
_symmetry_Int_Tables_number   1
_cell_volume   192.799
_cell_formula_units_Z   1
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  0.000  1.0
  Al  Al1  1  0.654  0.346  0.654  1.0
  Al  Al2  1  0.346  0.654  0.346  1.0
  Al  Al3  1  0.000  0.329  0.329  1.0
  Al  Al4  1  0.000  0.671  0.671  1.0
  Al  Al5  1  0.693  0.807  0.193  1.0
  Al  Al6  1  0.307  0.193  0.807  1.0
  Cr  Cr7  1  0.500  0.000  0.500  1.0
  Cr  Cr8  1  0.000  0.000  0.500  1.0
  Cr  Cr9  1  0.500  0.500  0.000  1.0
  Cr  Cr10  1  0.000  0.500  0.000  1.0
  Cr  Cr11  1  0.500  0.760  0.760  1.0
  Cr  Cr12  1  0.500  0.240  0.240  1.0
[/CIF]
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The material described by Er(CrAl)6 crystallizes in the orthorhombic Immm space group. Er(1) is bonded to four equivalent Cr(2), eight equivalent Cr(1), two equivalent Al(1), two equivalent Al(2), and four equivalent Al(3) atoms to form distorted ErAl8Cr12 hexagonal bipyramids that share corners with eight equivalent Er(1)Al8Cr12 hexagonal bipyramids, faces with eight equivalent Cr(2)Er2Al6Cr4 cuboctahedra, faces with sixteen equivalent Cr(1)Er2Al6Cr4 cuboctahedra, and faces with two equivalent Er(1)Al8Cr12 hexagonal bipyramids. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Er(1), two equivalent Cr(1), two equivalent Cr(2), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms to form distorted CrEr2Al6Cr4 cuboctahedra that share corners with four equivalent Cr(2)Er2Al6Cr4 cuboctahedra, corners with ten equivalent Cr(1)Er2Al6Cr4 cuboctahedra, edges with two equivalent Cr(2)Er2Al6Cr4 cuboctahedra, edges with four equivalent Cr(1)Er2Al6Cr4 cuboctahedra, faces with four equivalent Cr(2)Er2Al6Cr4 cuboctahedra, faces with six equivalent Cr(1)Er2Al6Cr4 cuboctahedra, and faces with four equivalent Er(1)Al8Cr12 hexagonal bipyramids. In the second Cr site, Cr(2) is bonded to two equivalent Er(1), four equivalent Cr(1), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms to form distorted CrEr2Al6Cr4 cuboctahedra that share corners with six equivalent Cr(2)Er2Al6Cr4 cuboctahedra, corners with eight equivalent Cr(1)Er2Al6Cr4 cuboctahedra, edges with three equivalent Cr(2)Er2Al6Cr4 cuboctahedra, edges with four equivalent Cr(1)Er2Al6Cr4 cuboctahedra,  a faceface with one Cr(2)Er2Al6Cr4 cuboctahedra, faces with eight equivalent Cr(1)Er2Al6Cr4 cuboctahedra, and faces with four equivalent Er(1)Al8Cr12 hexagonal bipyramids. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to one Er(1), two equivalent Cr(2), four equivalent Cr(1), one Al(1), and two equivalent Al(3) atoms. In the second Al site, Al(2) is bonded in a 7-coordinate geometry to one Er(1), two equivalent Cr(2), four equivalent Cr(1), and two equivalent Al(3) atoms. In the third Al site, Al(3) is bonded in a 12-coordinate geometry to two equivalent Er(1), two equivalent Cr(2), four equivalent Cr(1), two equivalent Al(1), and two equivalent Al(2) atoms. is represented by the CIF card [CIF]
data_Er(AlCr)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.064
_cell_length_b   6.670
_cell_length_c   6.670
_cell_angle_alpha   97.476
_cell_angle_beta   112.308
_cell_angle_gamma   67.692
_symmetry_Int_Tables_number   1
_cell_volume   192.799
_cell_formula_units_Z   1
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  0.000  1.0
  Al  Al1  1  0.654  0.346  0.654  1.0
  Al  Al2  1  0.346  0.654  0.346  1.0
  Al  Al3  1  0.000  0.329  0.329  1.0
  Al  Al4  1  0.000  0.671  0.671  1.0
  Al  Al5  1  0.693  0.807  0.193  1.0
  Al  Al6  1  0.307  0.193  0.807  1.0
  Cr  Cr7  1  0.500  0.000  0.500  1.0
  Cr  Cr8  1  0.000  0.000  0.500  1.0
  Cr  Cr9  1  0.500  0.500  0.000  1.0
  Cr  Cr10  1  0.000  0.500  0.000  1.0
  Cr  Cr11  1  0.500  0.760  0.760  1.0
  Cr  Cr12  1  0.500  0.240  0.240  1.0
[/CIF]
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