The structure described by Nd4Ag2Se7 crystallizes in the monoclinic Pc space group. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), one Se(7), and two equivalent Se(1) atoms. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one Se(3), one Se(7), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(4) atoms. In the third Nd site, Nd(3) is bonded in a 8-coordinate geometry to one Se(2), one Se(3), one Se(5), one Se(7), two equivalent Se(1), and two equivalent Se(4) atoms. In the fourth Nd site, Nd(4) is bonded to one Se(2), one Se(3), one Se(5), one Se(7), and two equivalent Se(6) atoms to form distorted corner-sharing NdSe6 pentagonal pyramids. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 6-coordinate geometry to one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(7) atom. In the second Ag site, Ag(2) is bonded in a 6-coordinate geometry to one Se(3), one Se(7), two equivalent Se(5), and two equivalent Se(6) atoms. There are seven inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Nd(1), two equivalent Nd(2), and two equivalent Nd(3) atoms. In the second Se site, Se(2) is bonded to one Nd(1), one Nd(3), one Nd(4), two equivalent Nd(2), and one Ag(1) atom to form distorted SeNd5Ag octahedra that share corners with two equivalent Se(7)Nd4Ag2 octahedra, corners with two equivalent Se(2)Nd5Ag octahedra, corners with three equivalent Se(3)Nd4Ag2 octahedra, edges with two equivalent Se(5)Nd3Ag3 octahedra, edges with two equivalent Se(7)Nd4Ag2 octahedra, and  a faceface with one Se(3)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 15-49°. In the third Se site, Se(3) is bonded to one Nd(1), one Nd(2), one Nd(3), one Nd(4), one Ag(1), and one Ag(2) atom to form distorted SeNd4Ag2 octahedra that share corners with two equivalent Se(5)Nd3Ag3 octahedra, corners with three equivalent Se(2)Nd5Ag octahedra, edges with two equivalent Se(5)Nd3Ag3 octahedra,  a faceface with one Se(2)Nd5Ag octahedra, and faces with two equivalent Se(7)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 15-64°. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to one Nd(1), two equivalent Nd(2), two equivalent Nd(3), and one Ag(1) atom. In the fifth Se site, Se(5) is bonded to one Nd(1), one Nd(3), one Nd(4), one Ag(1), and two equivalent Ag(2) atoms to form distorted SeNd3Ag3 octahedra that share corners with two equivalent Se(5)Nd3Ag3 octahedra, corners with two equivalent Se(3)Nd4Ag2 octahedra, corners with three equivalent Se(7)Nd4Ag2 octahedra, edges with two equivalent Se(3)Nd4Ag2 octahedra, edges with two equivalent Se(2)Nd5Ag octahedra, and  a faceface with one Se(7)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 14-64°. In the sixth Se site, Se(6) is bonded in a 6-coordinate geometry to one Nd(1), two equivalent Nd(4), one Ag(1), and two equivalent Ag(2) atoms. In the seventh Se site, Se(7) is bonded to one Nd(1), one Nd(2), one Nd(3), one Nd(4), one Ag(1), and one Ag(2) atom to form distorted SeNd4Ag2 octahedra that share corners with two equivalent Se(2)Nd5Ag octahedra, corners with three equivalent Se(5)Nd3Ag3 octahedra, edges with two equivalent Se(2)Nd5Ag octahedra,  a faceface with one Se(5)Nd3Ag3 octahedra, and faces with two equivalent Se(3)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 14-49°. is represented by the CIF card [CIF]
data_Nd4Ag2Se7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.392
_cell_length_b   7.518
_cell_length_c   7.856
_cell_angle_alpha   71.112
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   692.475
_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
  Nd  Nd0  1  0.206  0.176  0.203  1.0
  Nd  Nd1  1  0.939  0.555  0.053  1.0
  Nd  Nd2  1  0.061  0.555  0.553  1.0
  Nd  Nd3  1  0.794  0.176  0.703  1.0
  Nd  Nd4  1  0.852  0.985  0.261  1.0
  Nd  Nd5  1  0.148  0.985  0.761  1.0
  Nd  Nd6  1  0.371  0.482  0.752  1.0
  Nd  Nd7  1  0.629  0.482  0.252  1.0
  Ag  Ag8  1  0.685  0.691  0.686  1.0
  Ag  Ag9  1  0.444  0.096  0.552  1.0
  Ag  Ag10  1  0.556  0.096  0.052  1.0
  Ag  Ag11  1  0.315  0.691  0.186  1.0
  Se  Se12  1  0.005  0.237  0.383  1.0
  Se  Se13  1  0.169  0.562  0.917  1.0
  Se  Se14  1  0.831  0.562  0.417  1.0
  Se  Se15  1  0.709  0.851  0.004  1.0
  Se  Se16  1  0.068  0.828  0.182  1.0
  Se  Se17  1  0.654  0.045  0.450  1.0
  Se  Se18  1  0.346  0.045  0.950  1.0
  Se  Se19  1  0.932  0.828  0.682  1.0
  Se  Se20  1  0.424  0.397  0.136  1.0
  Se  Se21  1  0.251  0.343  0.506  1.0
  Se  Se22  1  0.576  0.397  0.636  1.0
  Se  Se23  1  0.995  0.237  0.883  1.0
  Se  Se24  1  0.749  0.343  0.006  1.0
  Se  Se25  1  0.291  0.851  0.504  1.0
[/CIF]
.
The structure described by Nd4Ag2Se7 crystallizes in the monoclinic Pc space group. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 8-coordinate geometry to one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), one Se(7), and two equivalent Se(1) atoms. In the second Nd site, Nd(2) is bonded in a 8-coordinate geometry to one Se(3), one Se(7), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(4) atoms. In the third Nd site, Nd(3) is bonded in a 8-coordinate geometry to one Se(2), one Se(3), one Se(5), one Se(7), two equivalent Se(1), and two equivalent Se(4) atoms. In the fourth Nd site, Nd(4) is bonded to one Se(2), one Se(3), one Se(5), one Se(7), and two equivalent Se(6) atoms to form distorted corner-sharing NdSe6 pentagonal pyramids. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 6-coordinate geometry to one Se(2), one Se(3), one Se(4), one Se(5), one Se(6), and one Se(7) atom. In the second Ag site, Ag(2) is bonded in a 6-coordinate geometry to one Se(3), one Se(7), two equivalent Se(5), and two equivalent Se(6) atoms. There are seven inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Nd(1), two equivalent Nd(2), and two equivalent Nd(3) atoms. In the second Se site, Se(2) is bonded to one Nd(1), one Nd(3), one Nd(4), two equivalent Nd(2), and one Ag(1) atom to form distorted SeNd5Ag octahedra that share corners with two equivalent Se(7)Nd4Ag2 octahedra, corners with two equivalent Se(2)Nd5Ag octahedra, corners with three equivalent Se(3)Nd4Ag2 octahedra, edges with two equivalent Se(5)Nd3Ag3 octahedra, edges with two equivalent Se(7)Nd4Ag2 octahedra, and  a faceface with one Se(3)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 15-49°. In the third Se site, Se(3) is bonded to one Nd(1), one Nd(2), one Nd(3), one Nd(4), one Ag(1), and one Ag(2) atom to form distorted SeNd4Ag2 octahedra that share corners with two equivalent Se(5)Nd3Ag3 octahedra, corners with three equivalent Se(2)Nd5Ag octahedra, edges with two equivalent Se(5)Nd3Ag3 octahedra,  a faceface with one Se(2)Nd5Ag octahedra, and faces with two equivalent Se(7)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 15-64°. In the fourth Se site, Se(4) is bonded in a 6-coordinate geometry to one Nd(1), two equivalent Nd(2), two equivalent Nd(3), and one Ag(1) atom. In the fifth Se site, Se(5) is bonded to one Nd(1), one Nd(3), one Nd(4), one Ag(1), and two equivalent Ag(2) atoms to form distorted SeNd3Ag3 octahedra that share corners with two equivalent Se(5)Nd3Ag3 octahedra, corners with two equivalent Se(3)Nd4Ag2 octahedra, corners with three equivalent Se(7)Nd4Ag2 octahedra, edges with two equivalent Se(3)Nd4Ag2 octahedra, edges with two equivalent Se(2)Nd5Ag octahedra, and  a faceface with one Se(7)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 14-64°. In the sixth Se site, Se(6) is bonded in a 6-coordinate geometry to one Nd(1), two equivalent Nd(4), one Ag(1), and two equivalent Ag(2) atoms. In the seventh Se site, Se(7) is bonded to one Nd(1), one Nd(2), one Nd(3), one Nd(4), one Ag(1), and one Ag(2) atom to form distorted SeNd4Ag2 octahedra that share corners with two equivalent Se(2)Nd5Ag octahedra, corners with three equivalent Se(5)Nd3Ag3 octahedra, edges with two equivalent Se(2)Nd5Ag octahedra,  a faceface with one Se(5)Nd3Ag3 octahedra, and faces with two equivalent Se(3)Nd4Ag2 octahedra. The corner-sharing octahedral tilt angles range from 14-49°. is represented by the CIF card [CIF]
data_Nd4Ag2Se7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.392
_cell_length_b   7.518
_cell_length_c   7.856
_cell_angle_alpha   71.112
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   692.475
_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
  Nd  Nd0  1  0.206  0.176  0.203  1.0
  Nd  Nd1  1  0.939  0.555  0.053  1.0
  Nd  Nd2  1  0.061  0.555  0.553  1.0
  Nd  Nd3  1  0.794  0.176  0.703  1.0
  Nd  Nd4  1  0.852  0.985  0.261  1.0
  Nd  Nd5  1  0.148  0.985  0.761  1.0
  Nd  Nd6  1  0.371  0.482  0.752  1.0
  Nd  Nd7  1  0.629  0.482  0.252  1.0
  Ag  Ag8  1  0.685  0.691  0.686  1.0
  Ag  Ag9  1  0.444  0.096  0.552  1.0
  Ag  Ag10  1  0.556  0.096  0.052  1.0
  Ag  Ag11  1  0.315  0.691  0.186  1.0
  Se  Se12  1  0.005  0.237  0.383  1.0
  Se  Se13  1  0.169  0.562  0.917  1.0
  Se  Se14  1  0.831  0.562  0.417  1.0
  Se  Se15  1  0.709  0.851  0.004  1.0
  Se  Se16  1  0.068  0.828  0.182  1.0
  Se  Se17  1  0.654  0.045  0.450  1.0
  Se  Se18  1  0.346  0.045  0.950  1.0
  Se  Se19  1  0.932  0.828  0.682  1.0
  Se  Se20  1  0.424  0.397  0.136  1.0
  Se  Se21  1  0.251  0.343  0.506  1.0
  Se  Se22  1  0.576  0.397  0.636  1.0
  Se  Se23  1  0.995  0.237  0.883  1.0
  Se  Se24  1  0.749  0.343  0.006  1.0
  Se  Se25  1  0.291  0.851  0.504  1.0
[/CIF]
.