The structure described by LuLa3Se6 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Lu sites. In the first Lu site, Lu(1) is bonded to two equivalent Se(5) and four equivalent Se(6) atoms to form LuSe6 octahedra that share edges with two equivalent Lu(1)Se6 octahedra and edges with four equivalent La(3)Se7 pentagonal bipyramids. In the second Lu site, Lu(2) is bonded to two equivalent Se(4) and four equivalent Se(2) atoms to form LuSe6 octahedra that share corners with two equivalent La(3)Se7 pentagonal bipyramids and edges with two equivalent Lu(2)Se6 octahedra. There are three inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one Se(3), one Se(6), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(5) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one Se(2), one Se(6), two equivalent Se(1), two equivalent Se(3), and two equivalent Se(4) atoms. In the third La site, La(3) is bonded to one Se(1), one Se(4), one Se(6), two equivalent Se(3), and two equivalent Se(5) atoms to form distorted LaSe7 pentagonal bipyramids that share  a cornercorner with one Lu(2)Se6 octahedra, edges with two equivalent Lu(1)Se6 octahedra, and edges with two equivalent La(3)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. There are six inequivalent Se sites. In the first Se site, Se(6) is bonded to two equivalent Lu(1), one La(1), one La(2), and one La(3) atom to form distorted SeLa3Lu2 trigonal bipyramids that share  a cornercorner with one Se(1)La5 trigonal bipyramid,  a cornercorner with one Se(3)La5 trigonal bipyramid, corners with three equivalent Se(2)La3Lu2 trigonal bipyramids, corners with four equivalent Se(6)La3Lu2 trigonal bipyramids, corners with three equivalent Se(4)La3Lu trigonal pyramids, edges with four equivalent Se(5)La4Lu square pyramids,  an edgeedge with one Se(6)La3Lu2 trigonal bipyramid, edges with two equivalent Se(1)La5 trigonal bipyramids, and edges with two equivalent Se(3)La5 trigonal bipyramids. In the second Se site, Se(1) is bonded to one La(3), two equivalent La(1), and two equivalent La(2) atoms to form distorted SeLa5 trigonal bipyramids that share corners with four equivalent Se(5)La4Lu square pyramids,  a cornercorner with one Se(6)La3Lu2 trigonal bipyramid, corners with two equivalent Se(3)La5 trigonal bipyramids, corners with four equivalent Se(2)La3Lu2 trigonal bipyramids, corners with two equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(5)La4Lu square pyramid,  an edgeedge with one Se(2)La3Lu2 trigonal bipyramid, edges with two equivalent Se(6)La3Lu2 trigonal bipyramids, edges with two equivalent Se(1)La5 trigonal bipyramids, edges with three equivalent Se(3)La5 trigonal bipyramids, and  a faceface with one Se(4)La3Lu trigonal pyramid. In the third Se site, Se(2) is bonded to two equivalent Lu(2), one La(2), and two equivalent La(1) atoms to form distorted SeLa3Lu2 trigonal bipyramids that share corners with two equivalent Se(5)La4Lu square pyramids, corners with two equivalent Se(2)La3Lu2 trigonal bipyramids, corners with three equivalent Se(6)La3Lu2 trigonal bipyramids, corners with four equivalent Se(1)La5 trigonal bipyramids, corners with two equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(5)La4Lu square pyramid,  an edgeedge with one Se(1)La5 trigonal bipyramid, edges with two equivalent Se(3)La5 trigonal bipyramids, edges with three equivalent Se(2)La3Lu2 trigonal bipyramids, and edges with two equivalent Se(4)La3Lu trigonal pyramids. In the fourth Se site, Se(3) is bonded to one La(1), two equivalent La(2), and two equivalent La(3) atoms to form distorted SeLa5 trigonal bipyramids that share corners with four equivalent Se(5)La4Lu square pyramids,  a cornercorner with one Se(6)La3Lu2 trigonal bipyramid, corners with two equivalent Se(1)La5 trigonal bipyramids, corners with four equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(5)La4Lu square pyramid, edges with two equivalent Se(2)La3Lu2 trigonal bipyramids, edges with two equivalent Se(6)La3Lu2 trigonal bipyramids, edges with two equivalent Se(3)La5 trigonal bipyramids, edges with three equivalent Se(1)La5 trigonal bipyramids, and  an edgeedge with one Se(4)La3Lu trigonal pyramid. In the fifth Se site, Se(4) is bonded to one Lu(2), one La(3), and two equivalent La(2) atoms to form distorted SeLa3Lu trigonal pyramids that share corners with two equivalent Se(5)La4Lu square pyramids, corners with two equivalent Se(2)La3Lu2 trigonal bipyramids, corners with two equivalent Se(1)La5 trigonal bipyramids, corners with three equivalent Se(6)La3Lu2 trigonal bipyramids, corners with four equivalent Se(3)La5 trigonal bipyramids, corners with three equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(3)La5 trigonal bipyramid, edges with two equivalent Se(2)La3Lu2 trigonal bipyramids, and  a faceface with one Se(1)La5 trigonal bipyramid. In the sixth Se site, Se(5) is bonded to one Lu(1), two equivalent La(1), and two equivalent La(3) atoms to form SeLa4Lu square pyramids that share  a cornercorner with one Se(5)La4Lu square pyramid, corners with two equivalent Se(2)La3Lu2 trigonal bipyramids, corners with four equivalent Se(1)La5 trigonal bipyramids, corners with four equivalent Se(3)La5 trigonal bipyramids, corners with two equivalent Se(4)La3Lu trigonal pyramids, edges with two equivalent Se(5)La4Lu square pyramids,  an edgeedge with one Se(2)La3Lu2 trigonal bipyramid,  an edgeedge with one Se(1)La5 trigonal bipyramid,  an edgeedge with one Se(3)La5 trigonal bipyramid, and edges with four equivalent Se(6)La3Lu2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_La3LuSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.182
_cell_length_b   14.749
_cell_length_c   17.736
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1093.907
_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
  La  La0  1  0.000  0.252  0.399  1.0
  La  La1  1  0.500  0.248  0.899  1.0
  La  La2  1  0.000  0.951  0.781  1.0
  La  La3  1  0.500  0.319  0.151  1.0
  La  La4  1  0.000  0.748  0.601  1.0
  La  La5  1  0.500  0.752  0.101  1.0
  La  La6  1  0.500  0.451  0.719  1.0
  La  La7  1  0.000  0.049  0.219  1.0
  La  La8  1  0.000  0.181  0.651  1.0
  La  La9  1  0.500  0.549  0.281  1.0
  La  La10  1  0.500  0.681  0.849  1.0
  La  La11  1  0.000  0.819  0.349  1.0
  Lu  Lu12  1  0.000  0.500  0.000  1.0
  Lu  Lu13  1  0.000  0.500  0.500  1.0
  Lu  Lu14  1  0.500  0.000  0.500  1.0
  Lu  Lu15  1  0.500  0.000  0.000  1.0
  Se  Se16  1  0.000  0.313  0.790  1.0
  Se  Se17  1  0.500  0.591  0.577  1.0
  Se  Se18  1  0.500  0.187  0.290  1.0
  Se  Se19  1  0.500  0.813  0.710  1.0
  Se  Se20  1  0.000  0.604  0.746  1.0
  Se  Se21  1  0.500  0.409  0.423  1.0
  Se  Se22  1  0.000  0.091  0.923  1.0
  Se  Se23  1  0.500  0.104  0.754  1.0
  Se  Se24  1  0.000  0.376  0.610  1.0
  Se  Se25  1  0.500  0.876  0.890  1.0
  Se  Se26  1  0.000  0.687  0.210  1.0
  Se  Se27  1  0.000  0.624  0.390  1.0
  Se  Se28  1  0.500  0.896  0.246  1.0
  Se  Se29  1  0.000  0.686  0.977  1.0
  Se  Se30  1  0.000  0.396  0.254  1.0
  Se  Se31  1  0.500  0.814  0.477  1.0
  Se  Se32  1  0.000  0.977  0.604  1.0
  Se  Se33  1  0.500  0.477  0.896  1.0
  Se  Se34  1  0.000  0.023  0.396  1.0
  Se  Se35  1  0.500  0.124  0.110  1.0
  Se  Se36  1  0.000  0.314  0.023  1.0
  Se  Se37  1  0.500  0.186  0.523  1.0
  Se  Se38  1  0.500  0.523  0.104  1.0
  Se  Se39  1  0.000  0.909  0.077  1.0
[/CIF]
.
The structure described by LuLa3Se6 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Lu sites. In the first Lu site, Lu(1) is bonded to two equivalent Se(5) and four equivalent Se(6) atoms to form LuSe6 octahedra that share edges with two equivalent Lu(1)Se6 octahedra and edges with four equivalent La(3)Se7 pentagonal bipyramids. In the second Lu site, Lu(2) is bonded to two equivalent Se(4) and four equivalent Se(2) atoms to form LuSe6 octahedra that share corners with two equivalent La(3)Se7 pentagonal bipyramids and edges with two equivalent Lu(2)Se6 octahedra. There are three inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one Se(3), one Se(6), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(5) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one Se(2), one Se(6), two equivalent Se(1), two equivalent Se(3), and two equivalent Se(4) atoms. In the third La site, La(3) is bonded to one Se(1), one Se(4), one Se(6), two equivalent Se(3), and two equivalent Se(5) atoms to form distorted LaSe7 pentagonal bipyramids that share  a cornercorner with one Lu(2)Se6 octahedra, edges with two equivalent Lu(1)Se6 octahedra, and edges with two equivalent La(3)Se7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. There are six inequivalent Se sites. In the first Se site, Se(6) is bonded to two equivalent Lu(1), one La(1), one La(2), and one La(3) atom to form distorted SeLa3Lu2 trigonal bipyramids that share  a cornercorner with one Se(1)La5 trigonal bipyramid,  a cornercorner with one Se(3)La5 trigonal bipyramid, corners with three equivalent Se(2)La3Lu2 trigonal bipyramids, corners with four equivalent Se(6)La3Lu2 trigonal bipyramids, corners with three equivalent Se(4)La3Lu trigonal pyramids, edges with four equivalent Se(5)La4Lu square pyramids,  an edgeedge with one Se(6)La3Lu2 trigonal bipyramid, edges with two equivalent Se(1)La5 trigonal bipyramids, and edges with two equivalent Se(3)La5 trigonal bipyramids. In the second Se site, Se(1) is bonded to one La(3), two equivalent La(1), and two equivalent La(2) atoms to form distorted SeLa5 trigonal bipyramids that share corners with four equivalent Se(5)La4Lu square pyramids,  a cornercorner with one Se(6)La3Lu2 trigonal bipyramid, corners with two equivalent Se(3)La5 trigonal bipyramids, corners with four equivalent Se(2)La3Lu2 trigonal bipyramids, corners with two equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(5)La4Lu square pyramid,  an edgeedge with one Se(2)La3Lu2 trigonal bipyramid, edges with two equivalent Se(6)La3Lu2 trigonal bipyramids, edges with two equivalent Se(1)La5 trigonal bipyramids, edges with three equivalent Se(3)La5 trigonal bipyramids, and  a faceface with one Se(4)La3Lu trigonal pyramid. In the third Se site, Se(2) is bonded to two equivalent Lu(2), one La(2), and two equivalent La(1) atoms to form distorted SeLa3Lu2 trigonal bipyramids that share corners with two equivalent Se(5)La4Lu square pyramids, corners with two equivalent Se(2)La3Lu2 trigonal bipyramids, corners with three equivalent Se(6)La3Lu2 trigonal bipyramids, corners with four equivalent Se(1)La5 trigonal bipyramids, corners with two equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(5)La4Lu square pyramid,  an edgeedge with one Se(1)La5 trigonal bipyramid, edges with two equivalent Se(3)La5 trigonal bipyramids, edges with three equivalent Se(2)La3Lu2 trigonal bipyramids, and edges with two equivalent Se(4)La3Lu trigonal pyramids. In the fourth Se site, Se(3) is bonded to one La(1), two equivalent La(2), and two equivalent La(3) atoms to form distorted SeLa5 trigonal bipyramids that share corners with four equivalent Se(5)La4Lu square pyramids,  a cornercorner with one Se(6)La3Lu2 trigonal bipyramid, corners with two equivalent Se(1)La5 trigonal bipyramids, corners with four equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(5)La4Lu square pyramid, edges with two equivalent Se(2)La3Lu2 trigonal bipyramids, edges with two equivalent Se(6)La3Lu2 trigonal bipyramids, edges with two equivalent Se(3)La5 trigonal bipyramids, edges with three equivalent Se(1)La5 trigonal bipyramids, and  an edgeedge with one Se(4)La3Lu trigonal pyramid. In the fifth Se site, Se(4) is bonded to one Lu(2), one La(3), and two equivalent La(2) atoms to form distorted SeLa3Lu trigonal pyramids that share corners with two equivalent Se(5)La4Lu square pyramids, corners with two equivalent Se(2)La3Lu2 trigonal bipyramids, corners with two equivalent Se(1)La5 trigonal bipyramids, corners with three equivalent Se(6)La3Lu2 trigonal bipyramids, corners with four equivalent Se(3)La5 trigonal bipyramids, corners with three equivalent Se(4)La3Lu trigonal pyramids,  an edgeedge with one Se(3)La5 trigonal bipyramid, edges with two equivalent Se(2)La3Lu2 trigonal bipyramids, and  a faceface with one Se(1)La5 trigonal bipyramid. In the sixth Se site, Se(5) is bonded to one Lu(1), two equivalent La(1), and two equivalent La(3) atoms to form SeLa4Lu square pyramids that share  a cornercorner with one Se(5)La4Lu square pyramid, corners with two equivalent Se(2)La3Lu2 trigonal bipyramids, corners with four equivalent Se(1)La5 trigonal bipyramids, corners with four equivalent Se(3)La5 trigonal bipyramids, corners with two equivalent Se(4)La3Lu trigonal pyramids, edges with two equivalent Se(5)La4Lu square pyramids,  an edgeedge with one Se(2)La3Lu2 trigonal bipyramid,  an edgeedge with one Se(1)La5 trigonal bipyramid,  an edgeedge with one Se(3)La5 trigonal bipyramid, and edges with four equivalent Se(6)La3Lu2 trigonal bipyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_La3LuSe6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.182
_cell_length_b   14.749
_cell_length_c   17.736
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1093.907
_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
  La  La0  1  0.000  0.252  0.399  1.0
  La  La1  1  0.500  0.248  0.899  1.0
  La  La2  1  0.000  0.951  0.781  1.0
  La  La3  1  0.500  0.319  0.151  1.0
  La  La4  1  0.000  0.748  0.601  1.0
  La  La5  1  0.500  0.752  0.101  1.0
  La  La6  1  0.500  0.451  0.719  1.0
  La  La7  1  0.000  0.049  0.219  1.0
  La  La8  1  0.000  0.181  0.651  1.0
  La  La9  1  0.500  0.549  0.281  1.0
  La  La10  1  0.500  0.681  0.849  1.0
  La  La11  1  0.000  0.819  0.349  1.0
  Lu  Lu12  1  0.000  0.500  0.000  1.0
  Lu  Lu13  1  0.000  0.500  0.500  1.0
  Lu  Lu14  1  0.500  0.000  0.500  1.0
  Lu  Lu15  1  0.500  0.000  0.000  1.0
  Se  Se16  1  0.000  0.313  0.790  1.0
  Se  Se17  1  0.500  0.591  0.577  1.0
  Se  Se18  1  0.500  0.187  0.290  1.0
  Se  Se19  1  0.500  0.813  0.710  1.0
  Se  Se20  1  0.000  0.604  0.746  1.0
  Se  Se21  1  0.500  0.409  0.423  1.0
  Se  Se22  1  0.000  0.091  0.923  1.0
  Se  Se23  1  0.500  0.104  0.754  1.0
  Se  Se24  1  0.000  0.376  0.610  1.0
  Se  Se25  1  0.500  0.876  0.890  1.0
  Se  Se26  1  0.000  0.687  0.210  1.0
  Se  Se27  1  0.000  0.624  0.390  1.0
  Se  Se28  1  0.500  0.896  0.246  1.0
  Se  Se29  1  0.000  0.686  0.977  1.0
  Se  Se30  1  0.000  0.396  0.254  1.0
  Se  Se31  1  0.500  0.814  0.477  1.0
  Se  Se32  1  0.000  0.977  0.604  1.0
  Se  Se33  1  0.500  0.477  0.896  1.0
  Se  Se34  1  0.000  0.023  0.396  1.0
  Se  Se35  1  0.500  0.124  0.110  1.0
  Se  Se36  1  0.000  0.314  0.023  1.0
  Se  Se37  1  0.500  0.186  0.523  1.0
  Se  Se38  1  0.500  0.523  0.104  1.0
  Se  Se39  1  0.000  0.909  0.077  1.0
[/CIF]
.