The material described by LaNi4Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Cmmm space group. La(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 10-coordinate geometry to three equivalent La(1), one Ni(1), four equivalent Ni(2), and two equivalent Si(1) atoms. In the second Ni site, Ni(2) is bonded to four equivalent La(1), two equivalent Ni(2), four equivalent Ni(1), and two equivalent Si(1) atoms to form NiLa4Si2Ni6 cuboctahedra that share corners with four equivalent Si(1)La4Ni8 cuboctahedra, corners with twelve equivalent Ni(2)La4Si2Ni6 cuboctahedra, edges with four equivalent Si(1)La4Ni8 cuboctahedra, edges with six equivalent Ni(2)La4Si2Ni6 cuboctahedra, faces with four equivalent Si(1)La4Ni8 cuboctahedra, and faces with six equivalent Ni(2)La4Si2Ni6 cuboctahedra. Si(1) is bonded to four equivalent La(1), four equivalent Ni(1), and four equivalent Ni(2) atoms to form distorted SiLa4Ni8 cuboctahedra that share corners with eight equivalent Ni(2)La4Si2Ni6 cuboctahedra, corners with eight equivalent Si(1)La4Ni8 cuboctahedra, edges with two equivalent Si(1)La4Ni8 cuboctahedra, edges with eight equivalent Ni(2)La4Si2Ni6 cuboctahedra, faces with two equivalent Si(1)La4Ni8 cuboctahedra, and faces with eight equivalent Ni(2)La4Si2Ni6 cuboctahedra. is represented by the CIF file [CIF]
data_LaSiNi4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.873
_cell_length_b   4.873
_cell_length_c   3.950
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   115.316
_symmetry_Int_Tables_number   1
_cell_volume   84.777
_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
  La  La0  1  0.000  0.000  0.000  1.0
  Si  Si1  1  0.500  0.500  0.500  1.0
  Ni  Ni2  1  0.342  0.658  0.000  1.0
  Ni  Ni3  1  0.658  0.342  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 material described by LaNi4Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Cmmm space group. La(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 10-coordinate geometry to three equivalent La(1), one Ni(1), four equivalent Ni(2), and two equivalent Si(1) atoms. In the second Ni site, Ni(2) is bonded to four equivalent La(1), two equivalent Ni(2), four equivalent Ni(1), and two equivalent Si(1) atoms to form NiLa4Si2Ni6 cuboctahedra that share corners with four equivalent Si(1)La4Ni8 cuboctahedra, corners with twelve equivalent Ni(2)La4Si2Ni6 cuboctahedra, edges with four equivalent Si(1)La4Ni8 cuboctahedra, edges with six equivalent Ni(2)La4Si2Ni6 cuboctahedra, faces with four equivalent Si(1)La4Ni8 cuboctahedra, and faces with six equivalent Ni(2)La4Si2Ni6 cuboctahedra. Si(1) is bonded to four equivalent La(1), four equivalent Ni(1), and four equivalent Ni(2) atoms to form distorted SiLa4Ni8 cuboctahedra that share corners with eight equivalent Ni(2)La4Si2Ni6 cuboctahedra, corners with eight equivalent Si(1)La4Ni8 cuboctahedra, edges with two equivalent Si(1)La4Ni8 cuboctahedra, edges with eight equivalent Ni(2)La4Si2Ni6 cuboctahedra, faces with two equivalent Si(1)La4Ni8 cuboctahedra, and faces with eight equivalent Ni(2)La4Si2Ni6 cuboctahedra. is represented by the CIF file [CIF]
data_LaSiNi4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.873
_cell_length_b   4.873
_cell_length_c   3.950
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   115.316
_symmetry_Int_Tables_number   1
_cell_volume   84.777
_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
  La  La0  1  0.000  0.000  0.000  1.0
  Si  Si1  1  0.500  0.500  0.500  1.0
  Ni  Ni2  1  0.342  0.658  0.000  1.0
  Ni  Ni3  1  0.658  0.342  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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