data_VSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.6
_cell_length_b   3.6
_cell_length_c   6.32
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   VSe
_chemical_formula_sum   'V2 Se2'
_cell_volume   81.85
_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
  V  V2  1  0.0  0.0  0.0  1.0
  V  V3  1  0.8  0.8  0.0  1.0
  Se  Se0  1  0.0  0.8  0.73  1.0
  Se  Se1  1  0.8  0.0  0.59  1.0

data_VSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.09
_cell_length_b   5.09
_cell_length_c   6.32
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   VSe
_chemical_formula_sum   'V4 Se4'
_cell_volume   163.71
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  V  V0  4  0.4  0.4  0.0  1.0
  Se  Se1  2  0.0  0.0  0.73  1.0
  Se  Se2  2  0.3  0.5  0.59  1.0

V V Se Se
V V Se Se 0 1 - - o 2 3 - + o 
VSe crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two VSe clusters. V(1) is bonded in a 2-coordinate geometry to one V(1) and one Se(1) atom. The V(1)-V(1) bond length is 1.02 Å. The V(1)-Se(1) bond length is 1.87 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent V(1) and one Se(2) atom. The Se(1)-Se(2) bond length is 1.33 Å. In the second Se site, Se(2) is bonded in a single-bond geometry to one Se(1) atom.