The material structure described by NiSe2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. Ni(1) is bonded to six equivalent Se(1) atoms to form NiSe6 octahedra that share corners with eight equivalent Ni(1)Se6 octahedra, corners with six equivalent Se(1)Ni3Se tetrahedra, and edges with two equivalent Ni(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 59°. Se(1) is bonded to three equivalent Ni(1) and one Se(1) atom to form distorted SeNi3Se tetrahedra that share corners with three equivalent Ni(1)Se6 octahedra, corners with thirteen equivalent Se(1)Ni3Se tetrahedra, and  an edgeedge with one Se(1)Ni3Se tetrahedra. The corner-sharing octahedral tilt angles range from 73-78°. is represented by the CIF file [CIF]
data_NiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.650
_cell_length_b   4.892
_cell_length_c   5.989
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   106.934
_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
  Ni  Ni0  1  0.500  0.500  0.500  1.0
  Ni  Ni1  1  0.000  0.000  0.000  1.0
  Se  Se2  1  0.500  0.294  0.877  1.0
  Se  Se3  1  0.500  0.706  0.123  1.0
  Se  Se4  1  0.000  0.206  0.377  1.0
  Se  Se5  1  0.000  0.794  0.623  1.0
[/CIF]
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The material structure described by NiSe2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. Ni(1) is bonded to six equivalent Se(1) atoms to form NiSe6 octahedra that share corners with eight equivalent Ni(1)Se6 octahedra, corners with six equivalent Se(1)Ni3Se tetrahedra, and edges with two equivalent Ni(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 59°. Se(1) is bonded to three equivalent Ni(1) and one Se(1) atom to form distorted SeNi3Se tetrahedra that share corners with three equivalent Ni(1)Se6 octahedra, corners with thirteen equivalent Se(1)Ni3Se tetrahedra, and  an edgeedge with one Se(1)Ni3Se tetrahedra. The corner-sharing octahedral tilt angles range from 73-78°. is represented by the CIF file [CIF]
data_NiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.650
_cell_length_b   4.892
_cell_length_c   5.989
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   106.934
_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
  Ni  Ni0  1  0.500  0.500  0.500  1.0
  Ni  Ni1  1  0.000  0.000  0.000  1.0
  Se  Se2  1  0.500  0.294  0.877  1.0
  Se  Se3  1  0.500  0.706  0.123  1.0
  Se  Se4  1  0.000  0.206  0.377  1.0
  Se  Se5  1  0.000  0.794  0.623  1.0
[/CIF]
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