The crystal structure described by Sm2Ni7 crystallizes in the trigonal R-3m space group. There are seven inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. In the second Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the third Sm site, Sm(2) is bonded in a 12-coordinate geometry to three equivalent Ni(1) and nine equivalent Ni(5) atoms. In the fourth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the fifth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the sixth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the seventh Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. There are eight inequivalent Ni sites. In the first Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. In the second Ni site, Ni(1) is bonded to six equivalent Sm(2) and six equivalent Ni(5) atoms to form NiSm6Ni6 cuboctahedra that share corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with six equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(5)Sm5Ni7 cuboctahedra. In the third Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Sm(1); three Ni(4,4); and three equivalent Ni(5) atoms. In the fourth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. In the fifth Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Sm(1), three equivalent Ni(4), and three equivalent Ni(5) atoms. In the sixth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. In the seventh Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. In the eighth Ni site, Ni(5) is bonded to two equivalent Sm(1), three equivalent Sm(2), one Ni(1), one Ni(2), one Ni(3), and four equivalent Ni(5) atoms to form distorted NiSm5Ni7 cuboctahedra that share corners with two equivalent Ni(1)Sm6Ni6 cuboctahedra, corners with six equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with nine equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with four equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with four equivalent Ni(5)Sm5Ni7 cuboctahedra,  a faceface with one Ni(4)Sm4Ni8 cuboctahedra, faces with three equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with ten equivalent Ni(5)Sm5Ni7 cuboctahedra. is represented by the CIF file [CIF]
data_Sm2Ni7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.955
_cell_length_b   4.955
_cell_length_c   12.550
_cell_angle_alpha   78.615
_cell_angle_beta   78.615
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   259.797
_cell_formula_units_Z   2
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
  Sm  Sm0  1  0.949  0.949  0.152  1.0
  Sm  Sm1  1  0.051  0.051  0.848  1.0
  Sm  Sm2  1  0.853  0.853  0.442  1.0
  Sm  Sm3  1  0.147  0.147  0.558  1.0
  Ni  Ni4  1  0.500  0.500  0.500  1.0
  Ni  Ni5  1  0.722  0.722  0.835  1.0
  Ni  Ni6  1  0.278  0.278  0.165  1.0
  Ni  Ni7  1  0.612  0.612  0.164  1.0
  Ni  Ni8  1  0.388  0.388  0.836  1.0
  Ni  Ni9  1  0.000  0.500  0.000  1.0
  Ni  Ni10  1  0.500  0.000  0.000  1.0
  Ni  Ni11  1  0.500  0.500  0.000  1.0
  Ni  Ni12  1  0.391  0.391  0.328  1.0
  Ni  Ni13  1  0.890  0.391  0.328  1.0
  Ni  Ni14  1  0.391  0.890  0.328  1.0
  Ni  Ni15  1  0.609  0.609  0.672  1.0
  Ni  Ni16  1  0.110  0.609  0.672  1.0
  Ni  Ni17  1  0.609  0.110  0.672  1.0
[/CIF]
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The crystal structure described by Sm2Ni7 crystallizes in the trigonal R-3m space group. There are seven inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. In the second Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the third Sm site, Sm(2) is bonded in a 12-coordinate geometry to three equivalent Ni(1) and nine equivalent Ni(5) atoms. In the fourth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the fifth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the sixth Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2); three equivalent Ni(3); six Ni(4,4); and six equivalent Ni(5) atoms. In the seventh Sm site, Sm(1) is bonded in a 18-coordinate geometry to three equivalent Ni(2), three equivalent Ni(3), six equivalent Ni(4), and six equivalent Ni(5) atoms. There are eight inequivalent Ni sites. In the first Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. In the second Ni site, Ni(1) is bonded to six equivalent Sm(2) and six equivalent Ni(5) atoms to form NiSm6Ni6 cuboctahedra that share corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with six equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with eighteen equivalent Ni(5)Sm5Ni7 cuboctahedra. In the third Ni site, Ni(2) is bonded in a 9-coordinate geometry to three equivalent Sm(1); three Ni(4,4); and three equivalent Ni(5) atoms. In the fourth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four Ni(4,4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra; corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra; edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra; edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra; faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra; and faces with eight Ni(4,4)Sm4Ni8 cuboctahedra. In the fifth Ni site, Ni(3) is bonded in a 9-coordinate geometry to three equivalent Sm(1), three equivalent Ni(4), and three equivalent Ni(5) atoms. In the sixth Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. In the seventh Ni site, Ni(4) is bonded to four Sm(1,1); two equivalent Ni(2); two equivalent Ni(3); and four equivalent Ni(4) atoms to form NiSm4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with twelve equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with two equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Sm5Ni7 cuboctahedra, faces with two equivalent Ni(5)Sm5Ni7 cuboctahedra, and faces with eight equivalent Ni(4)Sm4Ni8 cuboctahedra. In the eighth Ni site, Ni(5) is bonded to two equivalent Sm(1), three equivalent Sm(2), one Ni(1), one Ni(2), one Ni(3), and four equivalent Ni(5) atoms to form distorted NiSm5Ni7 cuboctahedra that share corners with two equivalent Ni(1)Sm6Ni6 cuboctahedra, corners with six equivalent Ni(4)Sm4Ni8 cuboctahedra, corners with nine equivalent Ni(5)Sm5Ni7 cuboctahedra, edges with four equivalent Ni(4)Sm4Ni8 cuboctahedra, edges with four equivalent Ni(5)Sm5Ni7 cuboctahedra,  a faceface with one Ni(4)Sm4Ni8 cuboctahedra, faces with three equivalent Ni(1)Sm6Ni6 cuboctahedra, and faces with ten equivalent Ni(5)Sm5Ni7 cuboctahedra. is represented by the CIF file [CIF]
data_Sm2Ni7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.955
_cell_length_b   4.955
_cell_length_c   12.550
_cell_angle_alpha   78.615
_cell_angle_beta   78.615
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   259.797
_cell_formula_units_Z   2
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
  Sm  Sm0  1  0.949  0.949  0.152  1.0
  Sm  Sm1  1  0.051  0.051  0.848  1.0
  Sm  Sm2  1  0.853  0.853  0.442  1.0
  Sm  Sm3  1  0.147  0.147  0.558  1.0
  Ni  Ni4  1  0.500  0.500  0.500  1.0
  Ni  Ni5  1  0.722  0.722  0.835  1.0
  Ni  Ni6  1  0.278  0.278  0.165  1.0
  Ni  Ni7  1  0.612  0.612  0.164  1.0
  Ni  Ni8  1  0.388  0.388  0.836  1.0
  Ni  Ni9  1  0.000  0.500  0.000  1.0
  Ni  Ni10  1  0.500  0.000  0.000  1.0
  Ni  Ni11  1  0.500  0.500  0.000  1.0
  Ni  Ni12  1  0.391  0.391  0.328  1.0
  Ni  Ni13  1  0.890  0.391  0.328  1.0
  Ni  Ni14  1  0.391  0.890  0.328  1.0
  Ni  Ni15  1  0.609  0.609  0.672  1.0
  Ni  Ni16  1  0.110  0.609  0.672  1.0
  Ni  Ni17  1  0.609  0.110  0.672  1.0
[/CIF]
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