The crystal structure described by Sm3CrSe6 crystallizes in the orthorhombic Pnnm space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(3), two equivalent Se(2), two equivalent Se(5), and two equivalent Se(6) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. In the third Sm site, Sm(3) is bonded to one Se(1), one Se(4), one Se(5), two equivalent Se(3), and two equivalent Se(6) atoms to form distorted SmSe7 pentagonal bipyramids that share  a cornercorner with one Cr(1)Se6 octahedra, edges with two equivalent Cr(2)Se6 octahedra, and edges with two equivalent Sm(3)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(4) and four equivalent Se(2) atoms to form CrSe6 octahedra that share corners with two equivalent Sm(3)Se7 pentagonal bipyramids and edges with two equivalent Cr(1)Se6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent Se(6) and four equivalent Se(1) atoms to form CrSe6 octahedra that share edges with two equivalent Cr(2)Se6 octahedra and edges with four equivalent Sm(3)Se7 pentagonal bipyramids. There are six inequivalent Se sites. In the first Se site, Se(5) is bonded to one Sm(3), two equivalent Sm(1), and two equivalent Sm(2) atoms to form distorted SeSm5 trigonal bipyramids that share  a cornercorner with one Se(1)Sm3Cr2 trigonal bipyramid, corners with two equivalent Se(3)Sm5 trigonal bipyramids, corners with four equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(6)Sm4Cr trigonal bipyramids,  an edgeedge with one Se(2)Sm3Cr2 trigonal bipyramid,  an edgeedge with one Se(6)Sm4Cr trigonal bipyramid, edges with two equivalent Se(1)Sm3Cr2 trigonal bipyramids, edges with two equivalent Se(5)Sm5 trigonal bipyramids, and edges with three equivalent Se(3)Sm5 trigonal bipyramids. In the second Se site, Se(6) is bonded to two equivalent Sm(1), two equivalent Sm(3), and one Cr(2) atom to form distorted SeSm4Cr trigonal bipyramids that share  a cornercorner with one Se(6)Sm4Cr trigonal bipyramid, corners with two equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(3)Sm5 trigonal bipyramids, corners with four equivalent Se(5)Sm5 trigonal bipyramids,  an edgeedge with one Se(2)Sm3Cr2 trigonal bipyramid,  an edgeedge with one Se(3)Sm5 trigonal bipyramid,  an edgeedge with one Se(5)Sm5 trigonal bipyramid, edges with two equivalent Se(6)Sm4Cr trigonal bipyramids, and edges with four equivalent Se(1)Sm3Cr2 trigonal bipyramids. In the third Se site, Se(1) is bonded to one Sm(1), one Sm(2), one Sm(3), and two equivalent Cr(2) atoms to form distorted SeSm3Cr2 trigonal bipyramids that share  a cornercorner with one Se(3)Sm5 trigonal bipyramid,  a cornercorner with one Se(5)Sm5 trigonal bipyramid, corners with three equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(1)Sm3Cr2 trigonal bipyramids,  an edgeedge with one Se(1)Sm3Cr2 trigonal bipyramid, edges with two equivalent Se(3)Sm5 trigonal bipyramids, edges with two equivalent Se(5)Sm5 trigonal bipyramids, and edges with four equivalent Se(6)Sm4Cr trigonal bipyramids. In the fourth Se site, Se(2) is bonded to one Sm(2), two equivalent Sm(1), and two equivalent Cr(1) atoms to form distorted SeSm3Cr2 trigonal bipyramids that share corners with two equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with two equivalent Se(6)Sm4Cr trigonal bipyramids, corners with three equivalent Se(1)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(5)Sm5 trigonal bipyramids,  an edgeedge with one Se(6)Sm4Cr trigonal bipyramid,  an edgeedge with one Se(5)Sm5 trigonal bipyramid, edges with two equivalent Se(3)Sm5 trigonal bipyramids, and edges with three equivalent Se(2)Sm3Cr2 trigonal bipyramids. In the fifth Se site, Se(3) is bonded to one Sm(1), two equivalent Sm(2), and two equivalent Sm(3) atoms to form distorted SeSm5 trigonal bipyramids that share  a cornercorner with one Se(1)Sm3Cr2 trigonal bipyramid, corners with two equivalent Se(5)Sm5 trigonal bipyramids, corners with four equivalent Se(6)Sm4Cr trigonal bipyramids,  an edgeedge with one Se(6)Sm4Cr trigonal bipyramid, edges with two equivalent Se(1)Sm3Cr2 trigonal bipyramids, edges with two equivalent Se(2)Sm3Cr2 trigonal bipyramids, edges with two equivalent Se(3)Sm5 trigonal bipyramids, and edges with three equivalent Se(5)Sm5 trigonal bipyramids. In the sixth Se site, Se(4) is bonded in a 4-coordinate geometry to one Sm(3), two equivalent Sm(2), and one Cr(1) atom. is represented by the CIF card [CIF]
data_Sm3CrSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.005
_cell_length_b   14.143
_cell_length_c   16.927
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   958.698
_cell_formula_units_Z   4
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  0.500  0.742  0.596  1.0
  Sm  Sm1  1  0.500  0.258  0.404  1.0
  Sm  Sm2  1  0.000  0.242  0.904  1.0
  Sm  Sm3  1  0.000  0.758  0.096  1.0
  Sm  Sm4  1  0.500  0.948  0.779  1.0
  Sm  Sm5  1  0.500  0.052  0.221  1.0
  Sm  Sm6  1  0.000  0.448  0.721  1.0
  Sm  Sm7  1  0.000  0.552  0.279  1.0
  Sm  Sm8  1  0.500  0.180  0.648  1.0
  Sm  Sm9  1  0.500  0.820  0.352  1.0
  Sm  Sm10  1  0.000  0.680  0.852  1.0
  Sm  Sm11  1  0.000  0.320  0.148  1.0
  Cr  Cr12  1  0.500  0.500  0.500  1.0
  Cr  Cr13  1  0.000  0.000  0.000  1.0
  Cr  Cr14  1  0.500  0.500  0.000  1.0
  Cr  Cr15  1  0.000  0.000  0.500  1.0
  Se  Se16  1  0.500  0.977  0.597  1.0
  Se  Se17  1  0.500  0.023  0.403  1.0
  Se  Se18  1  0.000  0.477  0.903  1.0
  Se  Se19  1  0.000  0.523  0.097  1.0
  Se  Se20  1  0.500  0.080  0.925  1.0
  Se  Se21  1  0.500  0.920  0.075  1.0
  Se  Se22  1  0.000  0.580  0.575  1.0
  Se  Se23  1  0.000  0.420  0.425  1.0
  Se  Se24  1  0.000  0.102  0.755  1.0
  Se  Se25  1  0.000  0.898  0.245  1.0
  Se  Se26  1  0.500  0.602  0.745  1.0
  Se  Se27  1  0.500  0.398  0.255  1.0
  Se  Se28  1  0.000  0.122  0.106  1.0
  Se  Se29  1  0.000  0.878  0.894  1.0
  Se  Se30  1  0.500  0.622  0.394  1.0
  Se  Se31  1  0.500  0.378  0.606  1.0
  Se  Se32  1  0.000  0.190  0.290  1.0
  Se  Se33  1  0.000  0.810  0.710  1.0
  Se  Se34  1  0.500  0.690  0.210  1.0
  Se  Se35  1  0.500  0.310  0.790  1.0
  Se  Se36  1  0.000  0.179  0.520  1.0
  Se  Se37  1  0.000  0.821  0.480  1.0
  Se  Se38  1  0.500  0.679  0.980  1.0
  Se  Se39  1  0.500  0.321  0.020  1.0
[/CIF]
.
The crystal structure described by Sm3CrSe6 crystallizes in the orthorhombic Pnnm space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(3), two equivalent Se(2), two equivalent Se(5), and two equivalent Se(6) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(4), and two equivalent Se(5) atoms. In the third Sm site, Sm(3) is bonded to one Se(1), one Se(4), one Se(5), two equivalent Se(3), and two equivalent Se(6) atoms to form distorted SmSe7 pentagonal bipyramids that share  a cornercorner with one Cr(1)Se6 octahedra, edges with two equivalent Cr(2)Se6 octahedra, and edges with two equivalent Sm(3)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(4) and four equivalent Se(2) atoms to form CrSe6 octahedra that share corners with two equivalent Sm(3)Se7 pentagonal bipyramids and edges with two equivalent Cr(1)Se6 octahedra. In the second Cr site, Cr(2) is bonded to two equivalent Se(6) and four equivalent Se(1) atoms to form CrSe6 octahedra that share edges with two equivalent Cr(2)Se6 octahedra and edges with four equivalent Sm(3)Se7 pentagonal bipyramids. There are six inequivalent Se sites. In the first Se site, Se(5) is bonded to one Sm(3), two equivalent Sm(1), and two equivalent Sm(2) atoms to form distorted SeSm5 trigonal bipyramids that share  a cornercorner with one Se(1)Sm3Cr2 trigonal bipyramid, corners with two equivalent Se(3)Sm5 trigonal bipyramids, corners with four equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(6)Sm4Cr trigonal bipyramids,  an edgeedge with one Se(2)Sm3Cr2 trigonal bipyramid,  an edgeedge with one Se(6)Sm4Cr trigonal bipyramid, edges with two equivalent Se(1)Sm3Cr2 trigonal bipyramids, edges with two equivalent Se(5)Sm5 trigonal bipyramids, and edges with three equivalent Se(3)Sm5 trigonal bipyramids. In the second Se site, Se(6) is bonded to two equivalent Sm(1), two equivalent Sm(3), and one Cr(2) atom to form distorted SeSm4Cr trigonal bipyramids that share  a cornercorner with one Se(6)Sm4Cr trigonal bipyramid, corners with two equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(3)Sm5 trigonal bipyramids, corners with four equivalent Se(5)Sm5 trigonal bipyramids,  an edgeedge with one Se(2)Sm3Cr2 trigonal bipyramid,  an edgeedge with one Se(3)Sm5 trigonal bipyramid,  an edgeedge with one Se(5)Sm5 trigonal bipyramid, edges with two equivalent Se(6)Sm4Cr trigonal bipyramids, and edges with four equivalent Se(1)Sm3Cr2 trigonal bipyramids. In the third Se site, Se(1) is bonded to one Sm(1), one Sm(2), one Sm(3), and two equivalent Cr(2) atoms to form distorted SeSm3Cr2 trigonal bipyramids that share  a cornercorner with one Se(3)Sm5 trigonal bipyramid,  a cornercorner with one Se(5)Sm5 trigonal bipyramid, corners with three equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(1)Sm3Cr2 trigonal bipyramids,  an edgeedge with one Se(1)Sm3Cr2 trigonal bipyramid, edges with two equivalent Se(3)Sm5 trigonal bipyramids, edges with two equivalent Se(5)Sm5 trigonal bipyramids, and edges with four equivalent Se(6)Sm4Cr trigonal bipyramids. In the fourth Se site, Se(2) is bonded to one Sm(2), two equivalent Sm(1), and two equivalent Cr(1) atoms to form distorted SeSm3Cr2 trigonal bipyramids that share corners with two equivalent Se(2)Sm3Cr2 trigonal bipyramids, corners with two equivalent Se(6)Sm4Cr trigonal bipyramids, corners with three equivalent Se(1)Sm3Cr2 trigonal bipyramids, corners with four equivalent Se(5)Sm5 trigonal bipyramids,  an edgeedge with one Se(6)Sm4Cr trigonal bipyramid,  an edgeedge with one Se(5)Sm5 trigonal bipyramid, edges with two equivalent Se(3)Sm5 trigonal bipyramids, and edges with three equivalent Se(2)Sm3Cr2 trigonal bipyramids. In the fifth Se site, Se(3) is bonded to one Sm(1), two equivalent Sm(2), and two equivalent Sm(3) atoms to form distorted SeSm5 trigonal bipyramids that share  a cornercorner with one Se(1)Sm3Cr2 trigonal bipyramid, corners with two equivalent Se(5)Sm5 trigonal bipyramids, corners with four equivalent Se(6)Sm4Cr trigonal bipyramids,  an edgeedge with one Se(6)Sm4Cr trigonal bipyramid, edges with two equivalent Se(1)Sm3Cr2 trigonal bipyramids, edges with two equivalent Se(2)Sm3Cr2 trigonal bipyramids, edges with two equivalent Se(3)Sm5 trigonal bipyramids, and edges with three equivalent Se(5)Sm5 trigonal bipyramids. In the sixth Se site, Se(4) is bonded in a 4-coordinate geometry to one Sm(3), two equivalent Sm(2), and one Cr(1) atom. is represented by the CIF card [CIF]
data_Sm3CrSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.005
_cell_length_b   14.143
_cell_length_c   16.927
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   958.698
_cell_formula_units_Z   4
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  0.500  0.742  0.596  1.0
  Sm  Sm1  1  0.500  0.258  0.404  1.0
  Sm  Sm2  1  0.000  0.242  0.904  1.0
  Sm  Sm3  1  0.000  0.758  0.096  1.0
  Sm  Sm4  1  0.500  0.948  0.779  1.0
  Sm  Sm5  1  0.500  0.052  0.221  1.0
  Sm  Sm6  1  0.000  0.448  0.721  1.0
  Sm  Sm7  1  0.000  0.552  0.279  1.0
  Sm  Sm8  1  0.500  0.180  0.648  1.0
  Sm  Sm9  1  0.500  0.820  0.352  1.0
  Sm  Sm10  1  0.000  0.680  0.852  1.0
  Sm  Sm11  1  0.000  0.320  0.148  1.0
  Cr  Cr12  1  0.500  0.500  0.500  1.0
  Cr  Cr13  1  0.000  0.000  0.000  1.0
  Cr  Cr14  1  0.500  0.500  0.000  1.0
  Cr  Cr15  1  0.000  0.000  0.500  1.0
  Se  Se16  1  0.500  0.977  0.597  1.0
  Se  Se17  1  0.500  0.023  0.403  1.0
  Se  Se18  1  0.000  0.477  0.903  1.0
  Se  Se19  1  0.000  0.523  0.097  1.0
  Se  Se20  1  0.500  0.080  0.925  1.0
  Se  Se21  1  0.500  0.920  0.075  1.0
  Se  Se22  1  0.000  0.580  0.575  1.0
  Se  Se23  1  0.000  0.420  0.425  1.0
  Se  Se24  1  0.000  0.102  0.755  1.0
  Se  Se25  1  0.000  0.898  0.245  1.0
  Se  Se26  1  0.500  0.602  0.745  1.0
  Se  Se27  1  0.500  0.398  0.255  1.0
  Se  Se28  1  0.000  0.122  0.106  1.0
  Se  Se29  1  0.000  0.878  0.894  1.0
  Se  Se30  1  0.500  0.622  0.394  1.0
  Se  Se31  1  0.500  0.378  0.606  1.0
  Se  Se32  1  0.000  0.190  0.290  1.0
  Se  Se33  1  0.000  0.810  0.710  1.0
  Se  Se34  1  0.500  0.690  0.210  1.0
  Se  Se35  1  0.500  0.310  0.790  1.0
  Se  Se36  1  0.000  0.179  0.520  1.0
  Se  Se37  1  0.000  0.821  0.480  1.0
  Se  Se38  1  0.500  0.679  0.980  1.0
  Se  Se39  1  0.500  0.321  0.020  1.0
[/CIF]
.