The crystal structure described by Ba2Sm3Si3SeO12 crystallizes in the hexagonal P6_3/m space group. Ba(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. Sm(1) is bonded in a 6-coordinate geometry to two equivalent Se(1), one O(2), one O(3), and four equivalent O(1) atoms. Si(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. Se(1) is bonded to six equivalent Sm(1) atoms to form SeSm6 octahedra that share corners with six equivalent O(3)Ba2SmSi tetrahedra and faces with two equivalent Se(1)Sm6 octahedra. There are three inequivalent O sites. In the first O site, O(3) is bonded to two equivalent Ba(1), one Sm(1), and one Si(1) atom to form distorted OBa2SmSi tetrahedra that share corners with two equivalent Se(1)Sm6 octahedra and edges with two equivalent O(3)Ba2SmSi tetrahedra. The corner-sharing octahedral tilt angles are 81°. In the second O site, O(1) is bonded in a 1-coordinate geometry to one Ba(1), two equivalent Sm(1), and one Si(1) atom. In the third O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Sm(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Ba2Sm3Si3SeO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.100
_cell_length_b   10.100
_cell_length_c   7.205
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   636.583
_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
  Ba  Ba0  1  0.667  0.333  0.998  1.0
  Ba  Ba1  1  0.333  0.667  0.002  1.0
  Ba  Ba2  1  0.333  0.667  0.498  1.0
  Ba  Ba3  1  0.667  0.333  0.502  1.0
  Sm  Sm4  1  0.733  0.996  0.750  1.0
  Sm  Sm5  1  0.267  0.004  0.250  1.0
  Sm  Sm6  1  0.262  0.267  0.750  1.0
  Sm  Sm7  1  0.738  0.733  0.250  1.0
  Sm  Sm8  1  0.004  0.738  0.750  1.0
  Sm  Sm9  1  0.996  0.262  0.250  1.0
  Si  Si10  1  0.979  0.361  0.750  1.0
  Si  Si11  1  0.021  0.639  0.250  1.0
  Si  Si12  1  0.382  0.021  0.750  1.0
  Si  Si13  1  0.618  0.979  0.250  1.0
  Si  Si14  1  0.639  0.618  0.750  1.0
  Si  Si15  1  0.361  0.382  0.250  1.0
  Se  Se16  1  0.000  0.000  0.000  1.0
  Se  Se17  1  0.000  0.000  0.500  1.0
  O  O18  1  0.901  0.247  0.931  1.0
  O  O19  1  0.099  0.753  0.069  1.0
  O  O20  1  0.346  0.099  0.931  1.0
  O  O21  1  0.099  0.753  0.431  1.0
  O  O22  1  0.654  0.901  0.069  1.0
  O  O23  1  0.901  0.247  0.569  1.0
  O  O24  1  0.753  0.654  0.931  1.0
  O  O25  1  0.654  0.901  0.431  1.0
  O  O26  1  0.247  0.346  0.069  1.0
  O  O27  1  0.346  0.099  0.569  1.0
  O  O28  1  0.247  0.346  0.431  1.0
  O  O29  1  0.753  0.654  0.569  1.0
  O  O30  1  0.919  0.486  0.750  1.0
  O  O31  1  0.081  0.514  0.250  1.0
  O  O32  1  0.567  0.081  0.750  1.0
  O  O33  1  0.433  0.919  0.250  1.0
  O  O34  1  0.514  0.433  0.750  1.0
  O  O35  1  0.486  0.567  0.250  1.0
  O  O36  1  0.555  0.720  0.750  1.0
  O  O37  1  0.445  0.280  0.250  1.0
  O  O38  1  0.166  0.445  0.750  1.0
  O  O39  1  0.834  0.555  0.250  1.0
  O  O40  1  0.280  0.834  0.750  1.0
  O  O41  1  0.720  0.166  0.250  1.0
[/CIF]
.
The crystal structure described by Ba2Sm3Si3SeO12 crystallizes in the hexagonal P6_3/m space group. Ba(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. Sm(1) is bonded in a 6-coordinate geometry to two equivalent Se(1), one O(2), one O(3), and four equivalent O(1) atoms. Si(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. Se(1) is bonded to six equivalent Sm(1) atoms to form SeSm6 octahedra that share corners with six equivalent O(3)Ba2SmSi tetrahedra and faces with two equivalent Se(1)Sm6 octahedra. There are three inequivalent O sites. In the first O site, O(3) is bonded to two equivalent Ba(1), one Sm(1), and one Si(1) atom to form distorted OBa2SmSi tetrahedra that share corners with two equivalent Se(1)Sm6 octahedra and edges with two equivalent O(3)Ba2SmSi tetrahedra. The corner-sharing octahedral tilt angles are 81°. In the second O site, O(1) is bonded in a 1-coordinate geometry to one Ba(1), two equivalent Sm(1), and one Si(1) atom. In the third O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Sm(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Ba2Sm3Si3SeO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.100
_cell_length_b   10.100
_cell_length_c   7.205
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   636.583
_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
  Ba  Ba0  1  0.667  0.333  0.998  1.0
  Ba  Ba1  1  0.333  0.667  0.002  1.0
  Ba  Ba2  1  0.333  0.667  0.498  1.0
  Ba  Ba3  1  0.667  0.333  0.502  1.0
  Sm  Sm4  1  0.733  0.996  0.750  1.0
  Sm  Sm5  1  0.267  0.004  0.250  1.0
  Sm  Sm6  1  0.262  0.267  0.750  1.0
  Sm  Sm7  1  0.738  0.733  0.250  1.0
  Sm  Sm8  1  0.004  0.738  0.750  1.0
  Sm  Sm9  1  0.996  0.262  0.250  1.0
  Si  Si10  1  0.979  0.361  0.750  1.0
  Si  Si11  1  0.021  0.639  0.250  1.0
  Si  Si12  1  0.382  0.021  0.750  1.0
  Si  Si13  1  0.618  0.979  0.250  1.0
  Si  Si14  1  0.639  0.618  0.750  1.0
  Si  Si15  1  0.361  0.382  0.250  1.0
  Se  Se16  1  0.000  0.000  0.000  1.0
  Se  Se17  1  0.000  0.000  0.500  1.0
  O  O18  1  0.901  0.247  0.931  1.0
  O  O19  1  0.099  0.753  0.069  1.0
  O  O20  1  0.346  0.099  0.931  1.0
  O  O21  1  0.099  0.753  0.431  1.0
  O  O22  1  0.654  0.901  0.069  1.0
  O  O23  1  0.901  0.247  0.569  1.0
  O  O24  1  0.753  0.654  0.931  1.0
  O  O25  1  0.654  0.901  0.431  1.0
  O  O26  1  0.247  0.346  0.069  1.0
  O  O27  1  0.346  0.099  0.569  1.0
  O  O28  1  0.247  0.346  0.431  1.0
  O  O29  1  0.753  0.654  0.569  1.0
  O  O30  1  0.919  0.486  0.750  1.0
  O  O31  1  0.081  0.514  0.250  1.0
  O  O32  1  0.567  0.081  0.750  1.0
  O  O33  1  0.433  0.919  0.250  1.0
  O  O34  1  0.514  0.433  0.750  1.0
  O  O35  1  0.486  0.567  0.250  1.0
  O  O36  1  0.555  0.720  0.750  1.0
  O  O37  1  0.445  0.280  0.250  1.0
  O  O38  1  0.166  0.445  0.750  1.0
  O  O39  1  0.834  0.555  0.250  1.0
  O  O40  1  0.280  0.834  0.750  1.0
  O  O41  1  0.720  0.166  0.250  1.0
[/CIF]
.