The structure described by Sm2Fe15Al2C crystallizes in the monoclinic C2/m space group. Sm(1) is bonded in a distorted single-bond geometry to one Fe(3), four equivalent Fe(6), six equivalent Fe(2), one Al(1), and one C(1) atom. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a single-bond geometry to two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(6), one Al(1), and one C(1) atom. In the second Fe site, Fe(2) is bonded to three equivalent Sm(1), one Fe(1), one Fe(2), one Fe(3), one Fe(4), one Fe(5), three equivalent Fe(6), and one Al(1) atom to form distorted FeSm3AlFe8 cuboctahedra that share  a cornercorner with one Fe(3)Sm2Al2Fe8 cuboctahedra, corners with seven equivalent Fe(2)Sm3AlFe8 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra,  an edgeedge with one Fe(3)Sm2Al2Fe8 cuboctahedra, edges with three equivalent Fe(2)Sm3AlFe8 cuboctahedra,  a faceface with one Fe(3)Sm2Al2Fe8 cuboctahedra, faces with four equivalent Fe(2)Sm3AlFe8 cuboctahedra, and  a faceface with one C(1)Sm2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 64-72°. In the third Fe site, Fe(3) is bonded to two equivalent Sm(1), four equivalent Fe(2), four equivalent Fe(6), and two equivalent Al(1) atoms to form distorted FeSm2Al2Fe8 cuboctahedra that share corners with four equivalent Fe(2)Sm3AlFe8 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra, edges with four equivalent Fe(2)Sm3AlFe8 cuboctahedra, and faces with four equivalent Fe(2)Sm3AlFe8 cuboctahedra. The corner-sharing octahedral tilt angles are 48°. In the fourth Fe site, Fe(4) is bonded in a 10-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Al(1) atoms. In the fifth Fe site, Fe(5) is bonded in a single-bond geometry to two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(6), two equivalent Al(1), and one C(1) atom. In the sixth Fe site, Fe(6) is bonded in a distorted q6 geometry to two equivalent Sm(1), one Fe(1), one Fe(3), one Fe(4), one Fe(5), one Fe(6), three equivalent Fe(2), and two equivalent Al(1) atoms. Al(1) is bonded in a 14-coordinate geometry to one Sm(1), one Fe(1), one Fe(3), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(5), four equivalent Fe(6), and one Al(1) atom. C(1) is bonded to two equivalent Sm(1), two equivalent Fe(1), and two equivalent Fe(5) atoms to form CSm2Fe4 octahedra that share corners with two equivalent Fe(3)Sm2Al2Fe8 cuboctahedra, corners with eight equivalent Fe(2)Sm3AlFe8 cuboctahedra, and faces with four equivalent Fe(2)Sm3AlFe8 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sm2Al2Fe15C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.490
_cell_length_b   6.490
_cell_length_c   6.470
_cell_angle_alpha   82.975
_cell_angle_beta   82.975
_cell_angle_gamma   82.829
_symmetry_Int_Tables_number   1
_cell_volume   266.817
_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
  Sm  Sm0  1  0.654  0.654  0.640  1.0
  Sm  Sm1  1  0.346  0.346  0.360  1.0
  Al  Al2  1  0.896  0.896  0.897  1.0
  Al  Al3  1  0.104  0.104  0.103  1.0
  Fe  Fe4  1  0.344  0.344  0.852  1.0
  Fe  Fe5  1  0.342  0.850  0.344  1.0
  Fe  Fe6  1  0.850  0.342  0.344  1.0
  Fe  Fe7  1  0.656  0.656  0.148  1.0
  Fe  Fe8  1  0.658  0.150  0.656  1.0
  Fe  Fe9  1  0.150  0.658  0.656  1.0
  Fe  Fe10  1  0.000  0.000  0.500  1.0
  Fe  Fe11  1  0.000  0.500  0.000  1.0
  Fe  Fe12  1  0.500  0.000  0.000  1.0
  Fe  Fe13  1  0.285  0.715  0.000  1.0
  Fe  Fe14  1  0.716  0.001  0.284  1.0
  Fe  Fe15  1  0.999  0.284  0.716  1.0
  Fe  Fe16  1  0.284  0.999  0.716  1.0
  Fe  Fe17  1  0.001  0.716  0.284  1.0
  Fe  Fe18  1  0.715  0.285  0.000  1.0
  C  C19  1  0.500  0.500  0.000  1.0
[/CIF]
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The structure described by Sm2Fe15Al2C crystallizes in the monoclinic C2/m space group. Sm(1) is bonded in a distorted single-bond geometry to one Fe(3), four equivalent Fe(6), six equivalent Fe(2), one Al(1), and one C(1) atom. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a single-bond geometry to two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(6), one Al(1), and one C(1) atom. In the second Fe site, Fe(2) is bonded to three equivalent Sm(1), one Fe(1), one Fe(2), one Fe(3), one Fe(4), one Fe(5), three equivalent Fe(6), and one Al(1) atom to form distorted FeSm3AlFe8 cuboctahedra that share  a cornercorner with one Fe(3)Sm2Al2Fe8 cuboctahedra, corners with seven equivalent Fe(2)Sm3AlFe8 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra,  an edgeedge with one Fe(3)Sm2Al2Fe8 cuboctahedra, edges with three equivalent Fe(2)Sm3AlFe8 cuboctahedra,  a faceface with one Fe(3)Sm2Al2Fe8 cuboctahedra, faces with four equivalent Fe(2)Sm3AlFe8 cuboctahedra, and  a faceface with one C(1)Sm2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 64-72°. In the third Fe site, Fe(3) is bonded to two equivalent Sm(1), four equivalent Fe(2), four equivalent Fe(6), and two equivalent Al(1) atoms to form distorted FeSm2Al2Fe8 cuboctahedra that share corners with four equivalent Fe(2)Sm3AlFe8 cuboctahedra, corners with two equivalent C(1)Sm2Fe4 octahedra, edges with four equivalent Fe(2)Sm3AlFe8 cuboctahedra, and faces with four equivalent Fe(2)Sm3AlFe8 cuboctahedra. The corner-sharing octahedral tilt angles are 48°. In the fourth Fe site, Fe(4) is bonded in a 10-coordinate geometry to two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Al(1) atoms. In the fifth Fe site, Fe(5) is bonded in a single-bond geometry to two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(6), two equivalent Al(1), and one C(1) atom. In the sixth Fe site, Fe(6) is bonded in a distorted q6 geometry to two equivalent Sm(1), one Fe(1), one Fe(3), one Fe(4), one Fe(5), one Fe(6), three equivalent Fe(2), and two equivalent Al(1) atoms. Al(1) is bonded in a 14-coordinate geometry to one Sm(1), one Fe(1), one Fe(3), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(5), four equivalent Fe(6), and one Al(1) atom. C(1) is bonded to two equivalent Sm(1), two equivalent Fe(1), and two equivalent Fe(5) atoms to form CSm2Fe4 octahedra that share corners with two equivalent Fe(3)Sm2Al2Fe8 cuboctahedra, corners with eight equivalent Fe(2)Sm3AlFe8 cuboctahedra, and faces with four equivalent Fe(2)Sm3AlFe8 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sm2Al2Fe15C
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.490
_cell_length_b   6.490
_cell_length_c   6.470
_cell_angle_alpha   82.975
_cell_angle_beta   82.975
_cell_angle_gamma   82.829
_symmetry_Int_Tables_number   1
_cell_volume   266.817
_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
  Sm  Sm0  1  0.654  0.654  0.640  1.0
  Sm  Sm1  1  0.346  0.346  0.360  1.0
  Al  Al2  1  0.896  0.896  0.897  1.0
  Al  Al3  1  0.104  0.104  0.103  1.0
  Fe  Fe4  1  0.344  0.344  0.852  1.0
  Fe  Fe5  1  0.342  0.850  0.344  1.0
  Fe  Fe6  1  0.850  0.342  0.344  1.0
  Fe  Fe7  1  0.656  0.656  0.148  1.0
  Fe  Fe8  1  0.658  0.150  0.656  1.0
  Fe  Fe9  1  0.150  0.658  0.656  1.0
  Fe  Fe10  1  0.000  0.000  0.500  1.0
  Fe  Fe11  1  0.000  0.500  0.000  1.0
  Fe  Fe12  1  0.500  0.000  0.000  1.0
  Fe  Fe13  1  0.285  0.715  0.000  1.0
  Fe  Fe14  1  0.716  0.001  0.284  1.0
  Fe  Fe15  1  0.999  0.284  0.716  1.0
  Fe  Fe16  1  0.284  0.999  0.716  1.0
  Fe  Fe17  1  0.001  0.716  0.284  1.0
  Fe  Fe18  1  0.715  0.285  0.000  1.0
  C  C19  1  0.500  0.500  0.000  1.0
[/CIF]
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