The material structure described by Eu3Al2As4 crystallizes in the monoclinic C2/c space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 6-coordinate geometry to two equivalent As(2) and four equivalent As(1) atoms. In the second Eu site, Eu(2) is bonded to two equivalent As(1) and four equivalent As(2) atoms to form distorted EuAs6 octahedra that share corners with four equivalent Al(1)As4 tetrahedra, edges with two equivalent Eu(2)As6 octahedra, and edges with four equivalent Al(1)As4 tetrahedra. Al(1) is bonded to two equivalent As(1) and two equivalent As(2) atoms to form AlAs4 tetrahedra that share corners with two equivalent Eu(2)As6 octahedra, corners with two equivalent Al(1)As4 tetrahedra, edges with two equivalent Eu(2)As6 octahedra, and  an edgeedge with one Al(1)As4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-57°. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 7-coordinate geometry to one Eu(2), four equivalent Eu(1), and two equivalent Al(1) atoms. In the second As site, As(2) is bonded in a 6-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), and two equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Eu3(AlAs2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.442
_cell_length_b   8.442
_cell_length_c   6.730
_cell_angle_alpha   89.795
_cell_angle_beta   89.794
_cell_angle_gamma   75.576
_symmetry_Int_Tables_number   1
_cell_volume   464.495
_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
  Eu  Eu0  1  0.751  0.007  0.967  1.0
  Eu  Eu1  1  0.993  0.249  0.533  1.0
  Eu  Eu2  1  0.249  0.993  0.033  1.0
  Eu  Eu3  1  0.007  0.751  0.467  1.0
  Eu  Eu4  1  0.599  0.401  0.250  1.0
  Eu  Eu5  1  0.401  0.599  0.750  1.0
  Al  Al6  1  0.581  0.829  0.416  1.0
  Al  Al7  1  0.171  0.419  0.084  1.0
  Al  Al8  1  0.419  0.171  0.584  1.0
  Al  Al9  1  0.829  0.581  0.916  1.0
  As  As10  1  0.712  0.060  0.474  1.0
  As  As11  1  0.940  0.288  0.026  1.0
  As  As12  1  0.288  0.940  0.526  1.0
  As  As13  1  0.060  0.712  0.974  1.0
  As  As14  1  0.573  0.742  0.068  1.0
  As  As15  1  0.258  0.427  0.432  1.0
  As  As16  1  0.427  0.258  0.932  1.0
  As  As17  1  0.742  0.573  0.568  1.0
[/CIF]
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The material structure described by Eu3Al2As4 crystallizes in the monoclinic C2/c space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 6-coordinate geometry to two equivalent As(2) and four equivalent As(1) atoms. In the second Eu site, Eu(2) is bonded to two equivalent As(1) and four equivalent As(2) atoms to form distorted EuAs6 octahedra that share corners with four equivalent Al(1)As4 tetrahedra, edges with two equivalent Eu(2)As6 octahedra, and edges with four equivalent Al(1)As4 tetrahedra. Al(1) is bonded to two equivalent As(1) and two equivalent As(2) atoms to form AlAs4 tetrahedra that share corners with two equivalent Eu(2)As6 octahedra, corners with two equivalent Al(1)As4 tetrahedra, edges with two equivalent Eu(2)As6 octahedra, and  an edgeedge with one Al(1)As4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-57°. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 7-coordinate geometry to one Eu(2), four equivalent Eu(1), and two equivalent Al(1) atoms. In the second As site, As(2) is bonded in a 6-coordinate geometry to two equivalent Eu(1), two equivalent Eu(2), and two equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Eu3(AlAs2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.442
_cell_length_b   8.442
_cell_length_c   6.730
_cell_angle_alpha   89.795
_cell_angle_beta   89.794
_cell_angle_gamma   75.576
_symmetry_Int_Tables_number   1
_cell_volume   464.495
_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
  Eu  Eu0  1  0.751  0.007  0.967  1.0
  Eu  Eu1  1  0.993  0.249  0.533  1.0
  Eu  Eu2  1  0.249  0.993  0.033  1.0
  Eu  Eu3  1  0.007  0.751  0.467  1.0
  Eu  Eu4  1  0.599  0.401  0.250  1.0
  Eu  Eu5  1  0.401  0.599  0.750  1.0
  Al  Al6  1  0.581  0.829  0.416  1.0
  Al  Al7  1  0.171  0.419  0.084  1.0
  Al  Al8  1  0.419  0.171  0.584  1.0
  Al  Al9  1  0.829  0.581  0.916  1.0
  As  As10  1  0.712  0.060  0.474  1.0
  As  As11  1  0.940  0.288  0.026  1.0
  As  As12  1  0.288  0.940  0.526  1.0
  As  As13  1  0.060  0.712  0.974  1.0
  As  As14  1  0.573  0.742  0.068  1.0
  As  As15  1  0.258  0.427  0.432  1.0
  As  As16  1  0.427  0.258  0.932  1.0
  As  As17  1  0.742  0.573  0.568  1.0
[/CIF]
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