The material structure described by U16N25 crystallizes in the trigonal R3 space group. There are six inequivalent U sites. In the first U site, U(1) is bonded to one N(1), one N(2), one N(6), one N(8), and two equivalent N(3) atoms to form distorted UN6 octahedra that share corners with two equivalent U(1)N6 octahedra, corners with two equivalent U(6)N6 octahedra, corners with two equivalent U(5)N7 pentagonal bipyramids,  an edgeedge with one U(3)N7 hexagonal pyramid,  an edgeedge with one U(6)N6 octahedra, edges with two equivalent U(2)N6 octahedra, and edges with two equivalent U(4)N6 octahedra. The corner-sharing octahedral tilt angles range from 59-62°. In the second U site, U(2) is bonded to one N(1), one N(2), one N(6), one N(8), and two equivalent N(5) atoms to form distorted UN6 octahedra that share corners with two equivalent U(2)N6 octahedra, corners with two equivalent U(4)N6 octahedra, corners with two equivalent U(6)N6 octahedra,  an edgeedge with one U(3)N7 hexagonal pyramid,  an edgeedge with one U(6)N6 octahedra, edges with two equivalent U(1)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 59-62°. In the third U site, U(3) is bonded to one N(9), three equivalent N(1), and three equivalent N(8) atoms to form distorted UN7 hexagonal pyramids that share corners with three equivalent U(4)N6 octahedra, edges with three equivalent U(1)N6 octahedra, edges with three equivalent U(2)N6 octahedra, and edges with three equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 55°. In the fourth U site, U(4) is bonded to one N(1), one N(3), one N(6), one N(7), and two equivalent N(4) atoms to form distorted UN6 octahedra that share  a cornercorner with one U(3)N7 hexagonal pyramid,  a cornercorner with one U(6)N6 octahedra, corners with two equivalent U(2)N6 octahedra, corners with two equivalent U(4)N6 octahedra, edges with two equivalent U(1)N6 octahedra, edges with two equivalent U(6)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 58-62°. In the fifth U site, U(5) is bonded to one N(2), one N(4), one N(5), one N(8), one N(9), and two equivalent N(7) atoms to form distorted UN7 pentagonal bipyramids that share  a cornercorner with one U(6)N6 octahedra, corners with two equivalent U(1)N6 octahedra,  an edgeedge with one U(3)N7 hexagonal pyramid, edges with two equivalent U(2)N6 octahedra, edges with two equivalent U(4)N6 octahedra, edges with two equivalent U(6)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 54-60°. In the sixth U site, U(6) is bonded to one N(2), one N(3), one N(4), one N(5), one N(6), and one N(7) atom to form distorted UN6 octahedra that share  a cornercorner with one U(4)N6 octahedra, corners with two equivalent U(1)N6 octahedra, corners with two equivalent U(2)N6 octahedra,  a cornercorner with one U(5)N7 pentagonal bipyramid,  an edgeedge with one U(1)N6 octahedra,  an edgeedge with one U(2)N6 octahedra, edges with two equivalent U(4)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 59-61°. There are nine inequivalent N sites. In the first N site, N(8) is bonded to one U(1), one U(2), one U(3), and one U(5) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the second N site, N(9) is bonded to one U(3) and three equivalent U(5) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the third N site, N(1) is bonded to one U(1), one U(2), one U(3), and one U(4) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the fourth N site, N(2) is bonded to one U(1), one U(2), one U(5), and one U(6) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the fifth N site, N(3) is bonded to one U(4), one U(6), and two equivalent U(1) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the sixth N site, N(4) is bonded to one U(5), one U(6), and two equivalent U(4) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the seventh N site, N(5) is bonded to one U(5), one U(6), and two equivalent U(2) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the eighth N site, N(6) is bonded to one U(1), one U(2), one U(4), and one U(6) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the ninth N site, N(7) is bonded to one U(4), one U(6), and two equivalent U(5) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_U16N25
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.236
_cell_length_b   9.236
_cell_length_c   9.236
_cell_angle_alpha   109.540
_cell_angle_beta   109.540
_cell_angle_gamma   109.540
_symmetry_Int_Tables_number   1
_cell_volume   605.046
_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
  U  U0  1  0.227  0.749  0.979  1.0
  U  U1  1  0.250  0.022  0.769  1.0
  U  U2  1  0.021  0.021  0.021  1.0
  U  U3  1  0.478  0.731  0.752  1.0
  U  U4  1  0.752  0.478  0.731  1.0
  U  U5  1  0.979  0.227  0.749  1.0
  U  U6  1  0.274  0.251  0.506  1.0
  U  U7  1  0.499  0.996  0.500  1.0
  U  U8  1  0.731  0.752  0.478  1.0
  U  U9  1  0.022  0.769  0.250  1.0
  U  U10  1  0.251  0.506  0.274  1.0
  U  U11  1  0.506  0.274  0.251  1.0
  U  U12  1  0.996  0.500  0.499  1.0
  U  U13  1  0.749  0.979  0.227  1.0
  U  U14  1  0.769  0.250  0.022  1.0
  U  U15  1  0.500  0.499  0.996  1.0
  N  N16  1  0.975  0.740  0.977  1.0
  N  N17  1  0.236  0.266  0.760  1.0
  N  N18  1  0.999  0.472  0.735  1.0
  N  N19  1  0.532  0.505  0.761  1.0
  N  N20  1  0.523  0.265  0.994  1.0
  N  N21  1  0.731  0.233  0.763  1.0
  N  N22  1  0.977  0.975  0.740  1.0
  N  N23  1  0.740  0.977  0.975  1.0
  N  N24  1  0.760  0.236  0.266  1.0
  N  N25  1  0.735  0.999  0.472  1.0
  N  N26  1  0.513  0.231  0.480  1.0
  N  N27  1  0.231  0.480  0.513  1.0
  N  N28  1  0.761  0.532  0.505  1.0
  N  N29  1  0.505  0.761  0.532  1.0
  N  N30  1  0.265  0.994  0.523  1.0
  N  N31  1  0.233  0.763  0.731  1.0
  N  N32  1  0.015  0.020  0.269  1.0
  N  N33  1  0.269  0.015  0.020  1.0
  N  N34  1  0.266  0.760  0.236  1.0
  N  N35  1  0.472  0.735  0.999  1.0
  N  N36  1  0.480  0.513  0.231  1.0
  N  N37  1  0.267  0.267  0.267  1.0
  N  N38  1  0.994  0.523  0.265  1.0
  N  N39  1  0.763  0.731  0.233  1.0
  N  N40  1  0.020  0.269  0.015  1.0
[/CIF]
.
The material structure described by U16N25 crystallizes in the trigonal R3 space group. There are six inequivalent U sites. In the first U site, U(1) is bonded to one N(1), one N(2), one N(6), one N(8), and two equivalent N(3) atoms to form distorted UN6 octahedra that share corners with two equivalent U(1)N6 octahedra, corners with two equivalent U(6)N6 octahedra, corners with two equivalent U(5)N7 pentagonal bipyramids,  an edgeedge with one U(3)N7 hexagonal pyramid,  an edgeedge with one U(6)N6 octahedra, edges with two equivalent U(2)N6 octahedra, and edges with two equivalent U(4)N6 octahedra. The corner-sharing octahedral tilt angles range from 59-62°. In the second U site, U(2) is bonded to one N(1), one N(2), one N(6), one N(8), and two equivalent N(5) atoms to form distorted UN6 octahedra that share corners with two equivalent U(2)N6 octahedra, corners with two equivalent U(4)N6 octahedra, corners with two equivalent U(6)N6 octahedra,  an edgeedge with one U(3)N7 hexagonal pyramid,  an edgeedge with one U(6)N6 octahedra, edges with two equivalent U(1)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 59-62°. In the third U site, U(3) is bonded to one N(9), three equivalent N(1), and three equivalent N(8) atoms to form distorted UN7 hexagonal pyramids that share corners with three equivalent U(4)N6 octahedra, edges with three equivalent U(1)N6 octahedra, edges with three equivalent U(2)N6 octahedra, and edges with three equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 55°. In the fourth U site, U(4) is bonded to one N(1), one N(3), one N(6), one N(7), and two equivalent N(4) atoms to form distorted UN6 octahedra that share  a cornercorner with one U(3)N7 hexagonal pyramid,  a cornercorner with one U(6)N6 octahedra, corners with two equivalent U(2)N6 octahedra, corners with two equivalent U(4)N6 octahedra, edges with two equivalent U(1)N6 octahedra, edges with two equivalent U(6)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 58-62°. In the fifth U site, U(5) is bonded to one N(2), one N(4), one N(5), one N(8), one N(9), and two equivalent N(7) atoms to form distorted UN7 pentagonal bipyramids that share  a cornercorner with one U(6)N6 octahedra, corners with two equivalent U(1)N6 octahedra,  an edgeedge with one U(3)N7 hexagonal pyramid, edges with two equivalent U(2)N6 octahedra, edges with two equivalent U(4)N6 octahedra, edges with two equivalent U(6)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 54-60°. In the sixth U site, U(6) is bonded to one N(2), one N(3), one N(4), one N(5), one N(6), and one N(7) atom to form distorted UN6 octahedra that share  a cornercorner with one U(4)N6 octahedra, corners with two equivalent U(1)N6 octahedra, corners with two equivalent U(2)N6 octahedra,  a cornercorner with one U(5)N7 pentagonal bipyramid,  an edgeedge with one U(1)N6 octahedra,  an edgeedge with one U(2)N6 octahedra, edges with two equivalent U(4)N6 octahedra, and edges with two equivalent U(5)N7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 59-61°. There are nine inequivalent N sites. In the first N site, N(8) is bonded to one U(1), one U(2), one U(3), and one U(5) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the second N site, N(9) is bonded to one U(3) and three equivalent U(5) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the third N site, N(1) is bonded to one U(1), one U(2), one U(3), and one U(4) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the fourth N site, N(2) is bonded to one U(1), one U(2), one U(5), and one U(6) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the fifth N site, N(3) is bonded to one U(4), one U(6), and two equivalent U(1) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the sixth N site, N(4) is bonded to one U(5), one U(6), and two equivalent U(4) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the seventh N site, N(5) is bonded to one U(5), one U(6), and two equivalent U(2) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. In the eighth N site, N(6) is bonded to one U(1), one U(2), one U(4), and one U(6) atom to form a mixture of edge and corner-sharing NU4 tetrahedra. In the ninth N site, N(7) is bonded to one U(4), one U(6), and two equivalent U(5) atoms to form a mixture of edge and corner-sharing NU4 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_U16N25
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.236
_cell_length_b   9.236
_cell_length_c   9.236
_cell_angle_alpha   109.540
_cell_angle_beta   109.540
_cell_angle_gamma   109.540
_symmetry_Int_Tables_number   1
_cell_volume   605.046
_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
  U  U0  1  0.227  0.749  0.979  1.0
  U  U1  1  0.250  0.022  0.769  1.0
  U  U2  1  0.021  0.021  0.021  1.0
  U  U3  1  0.478  0.731  0.752  1.0
  U  U4  1  0.752  0.478  0.731  1.0
  U  U5  1  0.979  0.227  0.749  1.0
  U  U6  1  0.274  0.251  0.506  1.0
  U  U7  1  0.499  0.996  0.500  1.0
  U  U8  1  0.731  0.752  0.478  1.0
  U  U9  1  0.022  0.769  0.250  1.0
  U  U10  1  0.251  0.506  0.274  1.0
  U  U11  1  0.506  0.274  0.251  1.0
  U  U12  1  0.996  0.500  0.499  1.0
  U  U13  1  0.749  0.979  0.227  1.0
  U  U14  1  0.769  0.250  0.022  1.0
  U  U15  1  0.500  0.499  0.996  1.0
  N  N16  1  0.975  0.740  0.977  1.0
  N  N17  1  0.236  0.266  0.760  1.0
  N  N18  1  0.999  0.472  0.735  1.0
  N  N19  1  0.532  0.505  0.761  1.0
  N  N20  1  0.523  0.265  0.994  1.0
  N  N21  1  0.731  0.233  0.763  1.0
  N  N22  1  0.977  0.975  0.740  1.0
  N  N23  1  0.740  0.977  0.975  1.0
  N  N24  1  0.760  0.236  0.266  1.0
  N  N25  1  0.735  0.999  0.472  1.0
  N  N26  1  0.513  0.231  0.480  1.0
  N  N27  1  0.231  0.480  0.513  1.0
  N  N28  1  0.761  0.532  0.505  1.0
  N  N29  1  0.505  0.761  0.532  1.0
  N  N30  1  0.265  0.994  0.523  1.0
  N  N31  1  0.233  0.763  0.731  1.0
  N  N32  1  0.015  0.020  0.269  1.0
  N  N33  1  0.269  0.015  0.020  1.0
  N  N34  1  0.266  0.760  0.236  1.0
  N  N35  1  0.472  0.735  0.999  1.0
  N  N36  1  0.480  0.513  0.231  1.0
  N  N37  1  0.267  0.267  0.267  1.0
  N  N38  1  0.994  0.523  0.265  1.0
  N  N39  1  0.763  0.731  0.233  1.0
  N  N40  1  0.020  0.269  0.015  1.0
[/CIF]
.