The structure described by Nd2Fe15(SiH)2 crystallizes in the monoclinic C2/m space group. Nd(1) is bonded in a distorted bent 120 degrees geometry to one Fe(3), two equivalent Fe(1), two equivalent Fe(4), three equivalent Fe(5), one Si(1), and two equivalent H(1) atoms. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Nd(1), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Si(1) atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with four equivalent H(1)Nd2Fe4 octahedra,  an edgeedge with one Fe(1)Nd2Fe8Si2 cuboctahedra, edges with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, edges with two equivalent H(1)Nd2Fe4 octahedra,  a faceface with one Fe(1)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, and faces with four equivalent Fe(5)Nd3Fe8Si cuboctahedra. The corner-sharing octahedral tilt angles range from 24-29°. In the second Fe site, Fe(2) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), two equivalent Si(1), and one H(1) atom. In the third Fe site, Fe(3) is bonded to two equivalent Nd(1), four equivalent Fe(2), four equivalent Fe(6), and two equivalent Si(1) atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with six equivalent Fe(5)Nd3Fe8Si cuboctahedra, edges with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, faces with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, faces with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, faces with four equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, and faces with four equivalent H(1)Nd2Fe4 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Si(1) atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with two equivalent H(1)Nd2Fe4 octahedra, edges with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, edges with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, faces with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, and faces with two equivalent H(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 47°. In the fifth Fe site, Fe(5) is bonded to three equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(6), and one Si(1) atom to form FeNd3Fe8Si cuboctahedra that share corners with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with three equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with four equivalent H(1)Nd2Fe4 octahedra,  an edgeedge with one Fe(3)Nd2Fe8Si2 cuboctahedra,  an edgeedge with one Fe(5)Nd3Fe8Si cuboctahedra, edges with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra,  a faceface with one Fe(3)Nd2Fe8Si2 cuboctahedra,  a faceface with one Fe(5)Nd3Fe8Si cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, faces with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, and faces with two equivalent H(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 63-71°. In the sixth Fe site, Fe(6) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), one Si(1), and one H(1) atom. Si(1) is bonded in a 14-coordinate geometry to one Nd(1), one Fe(3), one Fe(5), two equivalent Fe(1), two equivalent Fe(4), two equivalent Fe(6), four equivalent Fe(2), and one Si(1) atom. H(1) is bonded to two equivalent Nd(1), two equivalent Fe(2), and two equivalent Fe(6) atoms to form HNd2Fe4 octahedra that share corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with two equivalent H(1)Nd2Fe4 octahedra, edges with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, and faces with two equivalent Fe(5)Nd3Fe8Si cuboctahedra. The corner-sharing octahedral tilt angles are 61°. is represented by the CIF card [CIF]
data_Nd2Fe15(SiH)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.440
_cell_length_b   6.450
_cell_length_c   6.440
_cell_angle_alpha   82.325
_cell_angle_beta   82.434
_cell_angle_gamma   82.325
_symmetry_Int_Tables_number   1
_cell_volume   260.983
_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
  Nd  Nd0  1  0.651  0.655  0.651  1.0
  Nd  Nd1  1  0.349  0.345  0.349  1.0
  Fe  Fe2  1  0.715  0.000  0.285  1.0
  Fe  Fe3  1  0.000  0.281  0.719  1.0
  Fe  Fe4  1  0.281  0.719  1.000  1.0
  Fe  Fe5  1  1.000  0.719  0.281  1.0
  Fe  Fe6  1  0.719  0.281  0.000  1.0
  Fe  Fe7  1  0.285  0.000  0.715  1.0
  Fe  Fe8  1  0.000  0.500  0.000  1.0
  Fe  Fe9  1  0.500  0.000  0.000  1.0
  Fe  Fe10  1  0.000  0.000  0.500  1.0
  Fe  Fe11  1  0.339  0.847  0.339  1.0
  Fe  Fe12  1  0.848  0.340  0.340  1.0
  Fe  Fe13  1  0.340  0.340  0.848  1.0
  Fe  Fe14  1  0.661  0.153  0.661  1.0
  Fe  Fe15  1  0.152  0.660  0.660  1.0
  Fe  Fe16  1  0.660  0.660  0.152  1.0
  Si  Si17  1  0.899  0.898  0.899  1.0
  Si  Si18  1  0.101  0.102  0.101  1.0
  H  H19  1  0.000  0.500  0.500  1.0
  H  H20  1  0.500  0.500  0.000  1.0
[/CIF]
.
The structure described by Nd2Fe15(SiH)2 crystallizes in the monoclinic C2/m space group. Nd(1) is bonded in a distorted bent 120 degrees geometry to one Fe(3), two equivalent Fe(1), two equivalent Fe(4), three equivalent Fe(5), one Si(1), and two equivalent H(1) atoms. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Nd(1), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Si(1) atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with four equivalent H(1)Nd2Fe4 octahedra,  an edgeedge with one Fe(1)Nd2Fe8Si2 cuboctahedra, edges with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, edges with two equivalent H(1)Nd2Fe4 octahedra,  a faceface with one Fe(1)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, and faces with four equivalent Fe(5)Nd3Fe8Si cuboctahedra. The corner-sharing octahedral tilt angles range from 24-29°. In the second Fe site, Fe(2) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), two equivalent Si(1), and one H(1) atom. In the third Fe site, Fe(3) is bonded to two equivalent Nd(1), four equivalent Fe(2), four equivalent Fe(6), and two equivalent Si(1) atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with six equivalent Fe(5)Nd3Fe8Si cuboctahedra, edges with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, faces with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, faces with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, faces with four equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, and faces with four equivalent H(1)Nd2Fe4 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Si(1) atoms to form distorted FeNd2Fe8Si2 cuboctahedra that share corners with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with two equivalent H(1)Nd2Fe4 octahedra, edges with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, edges with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, faces with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(5)Nd3Fe8Si cuboctahedra, and faces with two equivalent H(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 47°. In the fifth Fe site, Fe(5) is bonded to three equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(6), and one Si(1) atom to form FeNd3Fe8Si cuboctahedra that share corners with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with three equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with four equivalent H(1)Nd2Fe4 octahedra,  an edgeedge with one Fe(3)Nd2Fe8Si2 cuboctahedra,  an edgeedge with one Fe(5)Nd3Fe8Si cuboctahedra, edges with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra,  a faceface with one Fe(3)Nd2Fe8Si2 cuboctahedra,  a faceface with one Fe(5)Nd3Fe8Si cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, faces with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, and faces with two equivalent H(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 63-71°. In the sixth Fe site, Fe(6) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), one Si(1), and one H(1) atom. Si(1) is bonded in a 14-coordinate geometry to one Nd(1), one Fe(3), one Fe(5), two equivalent Fe(1), two equivalent Fe(4), two equivalent Fe(6), four equivalent Fe(2), and one Si(1) atom. H(1) is bonded to two equivalent Nd(1), two equivalent Fe(2), and two equivalent Fe(6) atoms to form HNd2Fe4 octahedra that share corners with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe8Si cuboctahedra, corners with two equivalent H(1)Nd2Fe4 octahedra, edges with two equivalent Fe(1)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe8Si2 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe8Si2 cuboctahedra, and faces with two equivalent Fe(5)Nd3Fe8Si cuboctahedra. The corner-sharing octahedral tilt angles are 61°. is represented by the CIF card [CIF]
data_Nd2Fe15(SiH)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.440
_cell_length_b   6.450
_cell_length_c   6.440
_cell_angle_alpha   82.325
_cell_angle_beta   82.434
_cell_angle_gamma   82.325
_symmetry_Int_Tables_number   1
_cell_volume   260.983
_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
  Nd  Nd0  1  0.651  0.655  0.651  1.0
  Nd  Nd1  1  0.349  0.345  0.349  1.0
  Fe  Fe2  1  0.715  0.000  0.285  1.0
  Fe  Fe3  1  0.000  0.281  0.719  1.0
  Fe  Fe4  1  0.281  0.719  1.000  1.0
  Fe  Fe5  1  1.000  0.719  0.281  1.0
  Fe  Fe6  1  0.719  0.281  0.000  1.0
  Fe  Fe7  1  0.285  0.000  0.715  1.0
  Fe  Fe8  1  0.000  0.500  0.000  1.0
  Fe  Fe9  1  0.500  0.000  0.000  1.0
  Fe  Fe10  1  0.000  0.000  0.500  1.0
  Fe  Fe11  1  0.339  0.847  0.339  1.0
  Fe  Fe12  1  0.848  0.340  0.340  1.0
  Fe  Fe13  1  0.340  0.340  0.848  1.0
  Fe  Fe14  1  0.661  0.153  0.661  1.0
  Fe  Fe15  1  0.152  0.660  0.660  1.0
  Fe  Fe16  1  0.660  0.660  0.152  1.0
  Si  Si17  1  0.899  0.898  0.899  1.0
  Si  Si18  1  0.101  0.102  0.101  1.0
  H  H19  1  0.000  0.500  0.500  1.0
  H  H20  1  0.500  0.500  0.000  1.0
[/CIF]
.