data_Si4NiAg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   5.04
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si4NiAg
_chemical_formula_sum   'Si4 Ni1 Ag1'
_cell_volume   90.44
_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  Si2  1  0.46  0.46  0.67  1.0
  Si  Si3  1  0.46  0.67  0.46  1.0
  Si  Si4  1  0.67  0.46  0.46  1.0
  Si  Si5  1  0.67  0.67  0.67  1.0
  Ni  Ni1  1  0.0  0.0  0.0  1.0
  Ag  Ag0  1  0.34  0.34  0.34  1.0

data_Si4NiAg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.04
_cell_length_b   5.04
_cell_length_c   12.34
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Si4NiAg
_chemical_formula_sum   'Si12 Ni3 Ag3'
_cell_volume   271.32
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  9  0.07  0.14  0.47  1.0
  Si  Si1  3  0.0  0.0  0.33  1.0
  Ni  Ni2  3  0.0  0.0  0.0  1.0
  Ag  Ag3  3  0.0  0.0  0.66  1.0

Si Si Si Si Ni Ag
NiAgSi4 crystallizes in the trigonal R3m space group. Ni(1) is bonded in a hexagonal planar geometry to three equivalent Ag(1) and three equivalent Si(2) atoms. All Ni(1)-Ag(1) bond lengths are 2.91 Å. All Ni(1)-Si(2) bond lengths are 2.91 Å. Ag(1) is bonded to three equivalent Ni(1), three equivalent Si(2), and six equivalent Si(1) atoms to form a mixture of corner and edge-sharing AgSi9Ni3 cuboctahedra. All Ag(1)-Si(2) bond lengths are 2.91 Å. There are three shorter (2.35 Å) and three longer (2.95 Å) Ag(1)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 2-coordinate geometry to two equivalent Ag(1), one Si(2), and two equivalent Si(1) atoms. The Si(1)-Si(2) bond length is 1.82 Å. Both Si(1)-Si(1) bond lengths are 1.05 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to three equivalent Ni(1), three equivalent Ag(1), and three equivalent Si(1) atoms.