The material structure described by BaSrEuSeO6 is Orthorhombic Perovskite-derived structured and crystallizes in the orthorhombic P222 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form distorted BaO12 cuboctahedra that share faces with four equivalent Sr(1)O6 octahedra and faces with four equivalent Se(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a distorted q6 geometry to four equivalent O(4), four equivalent O(5), and four equivalent O(6) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(4) atoms. In the fourth Ba site, Ba(4) is bonded in a 4-coordinate geometry to four equivalent O(1) and four equivalent O(6) atoms. Sr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form SrO6 octahedra that share corners with six equivalent Se(1)O6 octahedra and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 18-25°. There are four inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(6) atoms. In the third Eu site, Eu(3) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. In the fourth Eu site, Eu(4) is bonded in a 4-coordinate geometry to four equivalent O(3) and four equivalent O(5) atoms. Se(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form SeO6 octahedra that share corners with six equivalent Sr(1)O6 octahedra and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 18-25°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 5-coordinate geometry to one Ba(2), one Sr(1), one Eu(1), one Eu(4), and one Se(1) atom. In the second O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(4), one Sr(1), one Eu(2), and one Se(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(4), one Sr(1), one Eu(1), and one Se(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(3), one Sr(1), one Eu(2), and one Se(1) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(1), one Eu(3), one Eu(4), and one Se(1) atom. In the sixth O site, O(4) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Sr(1), one Eu(3), and one Se(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaSrEuSeO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.413
_cell_length_b   8.429
_cell_length_c   8.455
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   599.587
_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
  Ba  Ba0  1  0.000  0.000  0.000  1.0
  Ba  Ba1  1  0.500  0.500  0.500  1.0
  Ba  Ba2  1  0.500  0.000  0.000  1.0
  Ba  Ba3  1  0.000  0.000  0.500  1.0
  Sr  Sr4  1  0.251  0.251  0.250  1.0
  Sr  Sr5  1  0.749  0.749  0.250  1.0
  Sr  Sr6  1  0.749  0.251  0.750  1.0
  Sr  Sr7  1  0.251  0.749  0.750  1.0
  Eu  Eu8  1  0.000  0.500  0.500  1.0
  Eu  Eu9  1  0.500  0.000  0.500  1.0
  Eu  Eu10  1  0.500  0.500  0.000  1.0
  Eu  Eu11  1  0.000  0.500  0.000  1.0
  Se  Se12  1  0.752  0.746  0.749  1.0
  Se  Se13  1  0.248  0.254  0.749  1.0
  Se  Se14  1  0.248  0.746  0.251  1.0
  Se  Se15  1  0.752  0.254  0.251  1.0
  O  O16  1  0.968  0.226  0.278  1.0
  O  O17  1  0.032  0.774  0.278  1.0
  O  O18  1  0.032  0.226  0.722  1.0
  O  O19  1  0.968  0.774  0.722  1.0
  O  O20  1  0.275  0.964  0.221  1.0
  O  O21  1  0.275  0.036  0.779  1.0
  O  O22  1  0.725  0.036  0.221  1.0
  O  O23  1  0.725  0.964  0.779  1.0
  O  O24  1  0.214  0.288  0.966  1.0
  O  O25  1  0.786  0.288  0.034  1.0
  O  O26  1  0.214  0.712  0.034  1.0
  O  O27  1  0.786  0.712  0.966  1.0
  O  O28  1  0.535  0.292  0.213  1.0
  O  O29  1  0.465  0.708  0.213  1.0
  O  O30  1  0.465  0.292  0.787  1.0
  O  O31  1  0.535  0.708  0.787  1.0
  O  O32  1  0.215  0.531  0.292  1.0
  O  O33  1  0.215  0.469  0.708  1.0
  O  O34  1  0.785  0.469  0.292  1.0
  O  O35  1  0.785  0.531  0.708  1.0
  O  O36  1  0.291  0.218  0.535  1.0
  O  O37  1  0.709  0.218  0.465  1.0
  O  O38  1  0.291  0.782  0.465  1.0
  O  O39  1  0.709  0.782  0.535  1.0
[/CIF]
.
The material structure described by BaSrEuSeO6 is Orthorhombic Perovskite-derived structured and crystallizes in the orthorhombic P222 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form distorted BaO12 cuboctahedra that share faces with four equivalent Sr(1)O6 octahedra and faces with four equivalent Se(1)O6 octahedra. In the second Ba site, Ba(2) is bonded in a distorted q6 geometry to four equivalent O(4), four equivalent O(5), and four equivalent O(6) atoms. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(4) atoms. In the fourth Ba site, Ba(4) is bonded in a 4-coordinate geometry to four equivalent O(1) and four equivalent O(6) atoms. Sr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form SrO6 octahedra that share corners with six equivalent Se(1)O6 octahedra and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 18-25°. There are four inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(6) atoms. In the third Eu site, Eu(3) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. In the fourth Eu site, Eu(4) is bonded in a 4-coordinate geometry to four equivalent O(3) and four equivalent O(5) atoms. Se(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form SeO6 octahedra that share corners with six equivalent Sr(1)O6 octahedra and  a faceface with one Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 18-25°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 5-coordinate geometry to one Ba(2), one Sr(1), one Eu(1), one Eu(4), and one Se(1) atom. In the second O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(4), one Sr(1), one Eu(2), and one Se(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(4), one Sr(1), one Eu(1), and one Se(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(3), one Sr(1), one Eu(2), and one Se(1) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(1), one Eu(3), one Eu(4), and one Se(1) atom. In the sixth O site, O(4) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Sr(1), one Eu(3), and one Se(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_BaSrEuSeO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.413
_cell_length_b   8.429
_cell_length_c   8.455
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   599.587
_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
  Ba  Ba0  1  0.000  0.000  0.000  1.0
  Ba  Ba1  1  0.500  0.500  0.500  1.0
  Ba  Ba2  1  0.500  0.000  0.000  1.0
  Ba  Ba3  1  0.000  0.000  0.500  1.0
  Sr  Sr4  1  0.251  0.251  0.250  1.0
  Sr  Sr5  1  0.749  0.749  0.250  1.0
  Sr  Sr6  1  0.749  0.251  0.750  1.0
  Sr  Sr7  1  0.251  0.749  0.750  1.0
  Eu  Eu8  1  0.000  0.500  0.500  1.0
  Eu  Eu9  1  0.500  0.000  0.500  1.0
  Eu  Eu10  1  0.500  0.500  0.000  1.0
  Eu  Eu11  1  0.000  0.500  0.000  1.0
  Se  Se12  1  0.752  0.746  0.749  1.0
  Se  Se13  1  0.248  0.254  0.749  1.0
  Se  Se14  1  0.248  0.746  0.251  1.0
  Se  Se15  1  0.752  0.254  0.251  1.0
  O  O16  1  0.968  0.226  0.278  1.0
  O  O17  1  0.032  0.774  0.278  1.0
  O  O18  1  0.032  0.226  0.722  1.0
  O  O19  1  0.968  0.774  0.722  1.0
  O  O20  1  0.275  0.964  0.221  1.0
  O  O21  1  0.275  0.036  0.779  1.0
  O  O22  1  0.725  0.036  0.221  1.0
  O  O23  1  0.725  0.964  0.779  1.0
  O  O24  1  0.214  0.288  0.966  1.0
  O  O25  1  0.786  0.288  0.034  1.0
  O  O26  1  0.214  0.712  0.034  1.0
  O  O27  1  0.786  0.712  0.966  1.0
  O  O28  1  0.535  0.292  0.213  1.0
  O  O29  1  0.465  0.708  0.213  1.0
  O  O30  1  0.465  0.292  0.787  1.0
  O  O31  1  0.535  0.708  0.787  1.0
  O  O32  1  0.215  0.531  0.292  1.0
  O  O33  1  0.215  0.469  0.708  1.0
  O  O34  1  0.785  0.469  0.292  1.0
  O  O35  1  0.785  0.531  0.708  1.0
  O  O36  1  0.291  0.218  0.535  1.0
  O  O37  1  0.709  0.218  0.465  1.0
  O  O38  1  0.291  0.782  0.465  1.0
  O  O39  1  0.709  0.782  0.535  1.0
[/CIF]
.