The compound described by Ni31Si12 crystallizes in the trigonal P321 space group. There are eight inequivalent Ni sites. In the first Ni site, Ni(5) is bonded in a 13-coordinate geometry to three equivalent Ni(3), six equivalent Ni(4), one Si(3), and three equivalent Si(1) atoms. In the second Ni site, Ni(6) is bonded in a 13-coordinate geometry to three equivalent Ni(2), six equivalent Ni(1), one Si(4), and three equivalent Si(2) atoms. In the third Ni site, Ni(7) is bonded in a 11-coordinate geometry to one Ni(7), three equivalent Ni(1), three equivalent Ni(2), one Si(5), and three equivalent Si(2) atoms. In the fourth Ni site, Ni(8) is bonded in a 11-coordinate geometry to six equivalent Ni(4), two equivalent Si(5), and three equivalent Si(1) atoms. In the fifth Ni site, Ni(1) is bonded in a 14-coordinate geometry to one Ni(3), one Ni(7), two equivalent Ni(6), three equivalent Ni(1), three equivalent Ni(2), one Si(3), and three equivalent Si(2) atoms. In the sixth Ni site, Ni(2) is bonded in a 13-coordinate geometry to one Ni(4), one Ni(6), one Ni(7), three equivalent Ni(1), three equivalent Ni(3), one Si(2), one Si(3), one Si(4), and one Si(5) atom. In the seventh Ni site, Ni(3) is bonded in a 12-coordinate geometry to one Ni(1), one Ni(5), three equivalent Ni(2), three equivalent Ni(4), one Si(1), one Si(3), one Si(4), and one Si(5) atom. In the eighth Ni site, Ni(4) is bonded in a 13-coordinate geometry to one Ni(2), one Ni(4), one Ni(8), two equivalent Ni(5), three equivalent Ni(3), one Si(4), one Si(5), and three equivalent Si(1) atoms. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Ni(8), two equivalent Ni(3), two equivalent Ni(5), and six equivalent Ni(4) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Ni(2), two equivalent Ni(6), two equivalent Ni(7), and six equivalent Ni(1) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to one Ni(5), three equivalent Ni(1), three equivalent Ni(2), and three equivalent Ni(3) atoms. In the fourth Si site, Si(4) is bonded in a distorted q6 geometry to one Ni(6), three equivalent Ni(2), three equivalent Ni(3), and three equivalent Ni(4) atoms. In the fifth Si site, Si(5) is bonded in a 11-coordinate geometry to one Ni(7), one Ni(8), three equivalent Ni(2), three equivalent Ni(3), and three equivalent Ni(4) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Si12Ni31
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.596
_cell_length_b   6.596
_cell_length_c   12.152
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   457.862
_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
  Si  Si0  1  0.649  0.649  0.500  1.0
  Si  Si1  1  0.000  0.351  0.500  1.0
  Si  Si2  1  0.351  0.000  0.500  1.0
  Si  Si3  1  0.318  0.318  0.000  1.0
  Si  Si4  1  0.000  0.682  0.000  1.0
  Si  Si5  1  0.682  0.000  0.000  1.0
  Si  Si6  1  0.667  0.333  0.227  1.0
  Si  Si7  1  0.333  0.667  0.773  1.0
  Si  Si8  1  0.667  0.333  0.725  1.0
  Si  Si9  1  0.333  0.667  0.275  1.0
  Si  Si10  1  0.000  0.000  0.707  1.0
  Si  Si11  1  0.000  0.000  0.293  1.0
  Ni  Ni12  1  0.078  0.412  0.905  1.0
  Ni  Ni13  1  0.665  0.963  0.198  1.0
  Ni  Ni14  1  0.037  0.702  0.198  1.0
  Ni  Ni15  1  0.298  0.335  0.198  1.0
  Ni  Ni16  1  0.702  0.037  0.802  1.0
  Ni  Ni17  1  0.335  0.298  0.802  1.0
  Ni  Ni18  1  0.963  0.665  0.802  1.0
  Ni  Ni19  1  0.358  0.033  0.305  1.0
  Ni  Ni20  1  0.967  0.325  0.305  1.0
  Ni  Ni21  1  0.675  0.642  0.305  1.0
  Ni  Ni22  1  0.325  0.967  0.695  1.0
  Ni  Ni23  1  0.642  0.675  0.695  1.0
  Ni  Ni24  1  0.033  0.358  0.695  1.0
  Ni  Ni25  1  0.633  0.941  0.404  1.0
  Ni  Ni26  1  0.059  0.692  0.404  1.0
  Ni  Ni27  1  0.308  0.367  0.404  1.0
  Ni  Ni28  1  0.692  0.059  0.596  1.0
  Ni  Ni29  1  0.367  0.308  0.596  1.0
  Ni  Ni30  1  0.941  0.633  0.596  1.0
  Ni  Ni31  1  0.588  0.667  0.905  1.0
  Ni  Ni32  1  0.333  0.922  0.905  1.0
  Ni  Ni33  1  0.667  0.588  0.095  1.0
  Ni  Ni34  1  0.922  0.333  0.095  1.0
  Ni  Ni35  1  0.412  0.078  0.095  1.0
  Ni  Ni36  1  0.667  0.333  0.433  1.0
  Ni  Ni37  1  0.333  0.667  0.567  1.0
  Ni  Ni38  1  0.667  0.333  0.927  1.0
  Ni  Ni39  1  0.333  0.667  0.073  1.0
  Ni  Ni40  1  0.000  0.000  0.903  1.0
  Ni  Ni41  1  0.000  0.000  0.097  1.0
  Ni  Ni42  1  0.000  0.000  0.500  1.0
[/CIF]
.
The compound described by Ni31Si12 crystallizes in the trigonal P321 space group. There are eight inequivalent Ni sites. In the first Ni site, Ni(5) is bonded in a 13-coordinate geometry to three equivalent Ni(3), six equivalent Ni(4), one Si(3), and three equivalent Si(1) atoms. In the second Ni site, Ni(6) is bonded in a 13-coordinate geometry to three equivalent Ni(2), six equivalent Ni(1), one Si(4), and three equivalent Si(2) atoms. In the third Ni site, Ni(7) is bonded in a 11-coordinate geometry to one Ni(7), three equivalent Ni(1), three equivalent Ni(2), one Si(5), and three equivalent Si(2) atoms. In the fourth Ni site, Ni(8) is bonded in a 11-coordinate geometry to six equivalent Ni(4), two equivalent Si(5), and three equivalent Si(1) atoms. In the fifth Ni site, Ni(1) is bonded in a 14-coordinate geometry to one Ni(3), one Ni(7), two equivalent Ni(6), three equivalent Ni(1), three equivalent Ni(2), one Si(3), and three equivalent Si(2) atoms. In the sixth Ni site, Ni(2) is bonded in a 13-coordinate geometry to one Ni(4), one Ni(6), one Ni(7), three equivalent Ni(1), three equivalent Ni(3), one Si(2), one Si(3), one Si(4), and one Si(5) atom. In the seventh Ni site, Ni(3) is bonded in a 12-coordinate geometry to one Ni(1), one Ni(5), three equivalent Ni(2), three equivalent Ni(4), one Si(1), one Si(3), one Si(4), and one Si(5) atom. In the eighth Ni site, Ni(4) is bonded in a 13-coordinate geometry to one Ni(2), one Ni(4), one Ni(8), two equivalent Ni(5), three equivalent Ni(3), one Si(4), one Si(5), and three equivalent Si(1) atoms. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Ni(8), two equivalent Ni(3), two equivalent Ni(5), and six equivalent Ni(4) atoms. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to two equivalent Ni(2), two equivalent Ni(6), two equivalent Ni(7), and six equivalent Ni(1) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to one Ni(5), three equivalent Ni(1), three equivalent Ni(2), and three equivalent Ni(3) atoms. In the fourth Si site, Si(4) is bonded in a distorted q6 geometry to one Ni(6), three equivalent Ni(2), three equivalent Ni(3), and three equivalent Ni(4) atoms. In the fifth Si site, Si(5) is bonded in a 11-coordinate geometry to one Ni(7), one Ni(8), three equivalent Ni(2), three equivalent Ni(3), and three equivalent Ni(4) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Si12Ni31
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.596
_cell_length_b   6.596
_cell_length_c   12.152
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   457.862
_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
  Si  Si0  1  0.649  0.649  0.500  1.0
  Si  Si1  1  0.000  0.351  0.500  1.0
  Si  Si2  1  0.351  0.000  0.500  1.0
  Si  Si3  1  0.318  0.318  0.000  1.0
  Si  Si4  1  0.000  0.682  0.000  1.0
  Si  Si5  1  0.682  0.000  0.000  1.0
  Si  Si6  1  0.667  0.333  0.227  1.0
  Si  Si7  1  0.333  0.667  0.773  1.0
  Si  Si8  1  0.667  0.333  0.725  1.0
  Si  Si9  1  0.333  0.667  0.275  1.0
  Si  Si10  1  0.000  0.000  0.707  1.0
  Si  Si11  1  0.000  0.000  0.293  1.0
  Ni  Ni12  1  0.078  0.412  0.905  1.0
  Ni  Ni13  1  0.665  0.963  0.198  1.0
  Ni  Ni14  1  0.037  0.702  0.198  1.0
  Ni  Ni15  1  0.298  0.335  0.198  1.0
  Ni  Ni16  1  0.702  0.037  0.802  1.0
  Ni  Ni17  1  0.335  0.298  0.802  1.0
  Ni  Ni18  1  0.963  0.665  0.802  1.0
  Ni  Ni19  1  0.358  0.033  0.305  1.0
  Ni  Ni20  1  0.967  0.325  0.305  1.0
  Ni  Ni21  1  0.675  0.642  0.305  1.0
  Ni  Ni22  1  0.325  0.967  0.695  1.0
  Ni  Ni23  1  0.642  0.675  0.695  1.0
  Ni  Ni24  1  0.033  0.358  0.695  1.0
  Ni  Ni25  1  0.633  0.941  0.404  1.0
  Ni  Ni26  1  0.059  0.692  0.404  1.0
  Ni  Ni27  1  0.308  0.367  0.404  1.0
  Ni  Ni28  1  0.692  0.059  0.596  1.0
  Ni  Ni29  1  0.367  0.308  0.596  1.0
  Ni  Ni30  1  0.941  0.633  0.596  1.0
  Ni  Ni31  1  0.588  0.667  0.905  1.0
  Ni  Ni32  1  0.333  0.922  0.905  1.0
  Ni  Ni33  1  0.667  0.588  0.095  1.0
  Ni  Ni34  1  0.922  0.333  0.095  1.0
  Ni  Ni35  1  0.412  0.078  0.095  1.0
  Ni  Ni36  1  0.667  0.333  0.433  1.0
  Ni  Ni37  1  0.333  0.667  0.567  1.0
  Ni  Ni38  1  0.667  0.333  0.927  1.0
  Ni  Ni39  1  0.333  0.667  0.073  1.0
  Ni  Ni40  1  0.000  0.000  0.903  1.0
  Ni  Ni41  1  0.000  0.000  0.097  1.0
  Ni  Ni42  1  0.000  0.000  0.500  1.0
[/CIF]
.