The structure described by Ti2NiSe4 crystallizes in the monoclinic C2/m space group. Ti(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form TiSe6 octahedra that share corners with six equivalent Ni(1)Se6 octahedra, edges with six equivalent Ti(1)Se6 octahedra, and  a faceface with one Ni(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. Ni(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form NiSe6 octahedra that share corners with twelve equivalent Ti(1)Se6 octahedra, edges with two equivalent Ni(1)Se6 octahedra, and faces with two equivalent Ti(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a rectangular see-saw-like geometry to three equivalent Ti(1) and one Ni(1) atom. In the second Se site, Se(1) is bonded to three equivalent Ti(1) and two equivalent Ni(1) atoms to form a mixture of distorted corner and edge-sharing SeTi3Ni2 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ti2NiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.592
_cell_length_b   6.171
_cell_length_c   6.915
_cell_angle_alpha   116.257
_cell_angle_beta   105.054
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   131.580
_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
  Ti  Ti0  1  0.748  0.739  0.495  1.0
  Ti  Ti1  1  0.252  0.261  0.505  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  Se  Se3  1  0.620  0.954  0.241  1.0
  Se  Se4  1  0.380  0.046  0.759  1.0
  Se  Se5  1  0.883  0.548  0.765  1.0
  Se  Se6  1  0.117  0.452  0.235  1.0
[/CIF]
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The structure described by Ti2NiSe4 crystallizes in the monoclinic C2/m space group. Ti(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form TiSe6 octahedra that share corners with six equivalent Ni(1)Se6 octahedra, edges with six equivalent Ti(1)Se6 octahedra, and  a faceface with one Ni(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. Ni(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form NiSe6 octahedra that share corners with twelve equivalent Ti(1)Se6 octahedra, edges with two equivalent Ni(1)Se6 octahedra, and faces with two equivalent Ti(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-49°. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded in a rectangular see-saw-like geometry to three equivalent Ti(1) and one Ni(1) atom. In the second Se site, Se(1) is bonded to three equivalent Ti(1) and two equivalent Ni(1) atoms to form a mixture of distorted corner and edge-sharing SeTi3Ni2 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ti2NiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.592
_cell_length_b   6.171
_cell_length_c   6.915
_cell_angle_alpha   116.257
_cell_angle_beta   105.054
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   131.580
_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
  Ti  Ti0  1  0.748  0.739  0.495  1.0
  Ti  Ti1  1  0.252  0.261  0.505  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  Se  Se3  1  0.620  0.954  0.241  1.0
  Se  Se4  1  0.380  0.046  0.759  1.0
  Se  Se5  1  0.883  0.548  0.765  1.0
  Se  Se6  1  0.117  0.452  0.235  1.0
[/CIF]
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