The compound described by CeNi4Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Cmmm space group. Ce(1) is bonded in a 18-coordinate geometry to six equivalent Ni(1), eight equivalent Ni(2), and four equivalent Si(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 12-coordinate geometry to three equivalent Ce(1), three equivalent Ni(1), four equivalent Ni(2), and two equivalent Si(1) atoms. In the second Ni site, Ni(2) is bonded to four equivalent Ce(1), two equivalent Ni(2), four equivalent Ni(1), and two equivalent Si(1) atoms to form NiCe4Si2Ni6 cuboctahedra that share corners with four equivalent Si(1)Ce4Ni8 cuboctahedra, corners with twelve equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, edges with four equivalent Si(1)Ce4Ni8 cuboctahedra, edges with six equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, faces with four equivalent Si(1)Ce4Ni8 cuboctahedra, and faces with six equivalent Ni(2)Ce4Si2Ni6 cuboctahedra. Si(1) is bonded to four equivalent Ce(1), four equivalent Ni(1), and four equivalent Ni(2) atoms to form distorted SiCe4Ni8 cuboctahedra that share corners with eight equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, corners with eight equivalent Si(1)Ce4Ni8 cuboctahedra, edges with two equivalent Si(1)Ce4Ni8 cuboctahedra, edges with eight equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, faces with two equivalent Si(1)Ce4Ni8 cuboctahedra, and faces with eight equivalent Ni(2)Ce4Si2Ni6 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeSiNi4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.754
_cell_length_b   4.754
_cell_length_c   4.002
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   116.158
_symmetry_Int_Tables_number   1
_cell_volume   81.180
_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
  Ce  Ce0  1  0.000  0.000  0.000  1.0
  Si  Si1  1  0.500  0.500  0.500  1.0
  Ni  Ni2  1  0.338  0.662  0.000  1.0
  Ni  Ni3  1  0.662  0.338  0.000  1.0
  Ni  Ni4  1  0.500  0.000  0.500  1.0
  Ni  Ni5  1  0.000  0.500  0.500  1.0
[/CIF]
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The compound described by CeNi4Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Cmmm space group. Ce(1) is bonded in a 18-coordinate geometry to six equivalent Ni(1), eight equivalent Ni(2), and four equivalent Si(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 12-coordinate geometry to three equivalent Ce(1), three equivalent Ni(1), four equivalent Ni(2), and two equivalent Si(1) atoms. In the second Ni site, Ni(2) is bonded to four equivalent Ce(1), two equivalent Ni(2), four equivalent Ni(1), and two equivalent Si(1) atoms to form NiCe4Si2Ni6 cuboctahedra that share corners with four equivalent Si(1)Ce4Ni8 cuboctahedra, corners with twelve equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, edges with four equivalent Si(1)Ce4Ni8 cuboctahedra, edges with six equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, faces with four equivalent Si(1)Ce4Ni8 cuboctahedra, and faces with six equivalent Ni(2)Ce4Si2Ni6 cuboctahedra. Si(1) is bonded to four equivalent Ce(1), four equivalent Ni(1), and four equivalent Ni(2) atoms to form distorted SiCe4Ni8 cuboctahedra that share corners with eight equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, corners with eight equivalent Si(1)Ce4Ni8 cuboctahedra, edges with two equivalent Si(1)Ce4Ni8 cuboctahedra, edges with eight equivalent Ni(2)Ce4Si2Ni6 cuboctahedra, faces with two equivalent Si(1)Ce4Ni8 cuboctahedra, and faces with eight equivalent Ni(2)Ce4Si2Ni6 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_CeSiNi4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.754
_cell_length_b   4.754
_cell_length_c   4.002
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   116.158
_symmetry_Int_Tables_number   1
_cell_volume   81.180
_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
  Ce  Ce0  1  0.000  0.000  0.000  1.0
  Si  Si1  1  0.500  0.500  0.500  1.0
  Ni  Ni2  1  0.338  0.662  0.000  1.0
  Ni  Ni3  1  0.662  0.338  0.000  1.0
  Ni  Ni4  1  0.500  0.000  0.500  1.0
  Ni  Ni5  1  0.000  0.500  0.500  1.0
[/CIF]
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