data_YNi3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.21
_cell_length_b   3.21
_cell_length_c   5.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YNi3
_chemical_formula_sum   'Y1 Ni3'
_cell_volume   58.91
_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
  Y  Y3  1  0.0  0.0  0.85  1.0
  Ni  Ni0  1  0.61  0.61  0.16  1.0
  Ni  Ni1  1  0.61  0.61  0.55  1.0
  Ni  Ni2  1  0.0  0.0  0.0  1.0

data_YNi3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.54
_cell_length_b   4.54
_cell_length_c   5.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   YNi3
_chemical_formula_sum   'Y2 Ni6'
_cell_volume   117.82
_cell_formula_units_Z   2
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
  Y  Y0  2  0.0  0.0  0.85  1.0
  Ni  Ni1  2  0.0  0.0  0.0  1.0
  Ni  Ni2  2  0.11  0.5  0.16  1.0
  Ni  Ni3  2  0.11  0.5  0.55  1.0

Y Ni Ni Ni
Y Ni Ni Ni 0 3 o o + 0 1 - - + 0 2 - - o 1 3 o + o 1 3 + o o 1 3 + + o 1 2 o o o 
YNi3 crystallizes in the monoclinic Cm space group. Y(1) is bonded in a single-bond geometry to one Ni(3) and four equivalent Ni(2) atoms. The Y(1)-Ni(3) bond length is 0.84 Å. There are a spread of Y(1)-Ni(2) bond distances ranging from 2.50-3.26 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 4-coordinate geometry to one Ni(2) and three equivalent Ni(3) atoms. The Ni(1)-Ni(2) bond length is 2.21 Å. There is one shorter (2.01 Å) and two longer (2.50 Å) Ni(1)-Ni(3) bond lengths. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to four equivalent Y(1) and one Ni(1) atom. In the third Ni site, Ni(3) is bonded in a single-bond geometry to one Y(1) and three equivalent Ni(1) atoms.