The material described by MgYbSe3 is Ilmenite-like structured and crystallizes in the trigonal R-3 space group. Mg(1) is bonded to six equivalent Se(1) atoms to form distorted MgSe6 octahedra that share corners with nine equivalent Yb(1)Se6 pentagonal pyramids, edges with three equivalent Mg(1)Se6 octahedra, and  a faceface with one Yb(1)Se6 pentagonal pyramid. Yb(1) is bonded to six equivalent Se(1) atoms to form distorted YbSe6 pentagonal pyramids that share corners with nine equivalent Mg(1)Se6 octahedra, edges with three equivalent Yb(1)Se6 pentagonal pyramids, and  a faceface with one Mg(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 39-67°. Se(1) is bonded to two equivalent Mg(1) and two equivalent Yb(1) atoms to form a mixture of distorted corner and edge-sharing SeYb2Mg2 tetrahedra. is represented by the CIF card [CIF]
data_YbMgSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.818
_cell_length_b   6.818
_cell_length_c   6.818
_cell_angle_alpha   66.529
_cell_angle_beta   66.529
_cell_angle_gamma   66.529
_symmetry_Int_Tables_number   1
_cell_volume   255.632
_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
  Mg  Mg0  1  0.150  0.150  0.150  1.0
  Mg  Mg1  1  0.850  0.850  0.850  1.0
  Se  Se2  1  0.578  0.977  0.202  1.0
  Se  Se3  1  0.422  0.023  0.798  1.0
  Se  Se4  1  0.202  0.578  0.977  1.0
  Se  Se5  1  0.798  0.422  0.023  1.0
  Se  Se6  1  0.977  0.202  0.578  1.0
  Se  Se7  1  0.023  0.798  0.422  1.0
  Yb  Yb8  1  0.370  0.370  0.370  1.0
  Yb  Yb9  1  0.630  0.630  0.630  1.0
[/CIF]
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The material described by MgYbSe3 is Ilmenite-like structured and crystallizes in the trigonal R-3 space group. Mg(1) is bonded to six equivalent Se(1) atoms to form distorted MgSe6 octahedra that share corners with nine equivalent Yb(1)Se6 pentagonal pyramids, edges with three equivalent Mg(1)Se6 octahedra, and  a faceface with one Yb(1)Se6 pentagonal pyramid. Yb(1) is bonded to six equivalent Se(1) atoms to form distorted YbSe6 pentagonal pyramids that share corners with nine equivalent Mg(1)Se6 octahedra, edges with three equivalent Yb(1)Se6 pentagonal pyramids, and  a faceface with one Mg(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 39-67°. Se(1) is bonded to two equivalent Mg(1) and two equivalent Yb(1) atoms to form a mixture of distorted corner and edge-sharing SeYb2Mg2 tetrahedra. is represented by the CIF card [CIF]
data_YbMgSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.818
_cell_length_b   6.818
_cell_length_c   6.818
_cell_angle_alpha   66.529
_cell_angle_beta   66.529
_cell_angle_gamma   66.529
_symmetry_Int_Tables_number   1
_cell_volume   255.632
_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
  Mg  Mg0  1  0.150  0.150  0.150  1.0
  Mg  Mg1  1  0.850  0.850  0.850  1.0
  Se  Se2  1  0.578  0.977  0.202  1.0
  Se  Se3  1  0.422  0.023  0.798  1.0
  Se  Se4  1  0.202  0.578  0.977  1.0
  Se  Se5  1  0.798  0.422  0.023  1.0
  Se  Se6  1  0.977  0.202  0.578  1.0
  Se  Se7  1  0.023  0.798  0.422  1.0
  Yb  Yb8  1  0.370  0.370  0.370  1.0
  Yb  Yb9  1  0.630  0.630  0.630  1.0
[/CIF]
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