The material described by MgHf8(N2O)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one N(1), one N(3), one N(7), and one O(4) atom to form MgN3O tetrahedra that share  a cornercorner with one Hf(1)N4O2 octahedra,  a cornercorner with one Hf(6)N4O2 octahedra, corners with three equivalent Hf(4)N3O tetrahedra, and corners with three equivalent Hf(8)N3O tetrahedra. The corner-sharing octahedral tilt angles range from 49-67°. There are eight inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one N(1), one N(2), one N(4), one N(6), one O(1), and one O(2) atom to form distorted HfN4O2 octahedra that share  a cornercorner with one Mg(1)N3O tetrahedra,  a cornercorner with one Hf(4)N3O tetrahedra, and edges with three equivalent Hf(6)N4O2 octahedra. In the second Hf site, Hf(2) is bonded in a distorted see-saw-like geometry to one N(2), one N(5), one N(8), and one O(3) atom. In the third Hf site, Hf(3) is bonded in a 5-coordinate geometry to one N(2), one N(5), one N(6), one N(8), and one O(3) atom. In the fourth Hf site, Hf(4) is bonded to one N(3), one N(4), one N(7), and one O(4) atom to form HfN3O tetrahedra that share  a cornercorner with one Hf(1)N4O2 octahedra,  a cornercorner with one Hf(6)N4O2 octahedra, corners with three equivalent Mg(1)N3O tetrahedra, and corners with three equivalent Hf(8)N3O tetrahedra. The corner-sharing octahedral tilt angles range from 55-69°. In the fifth Hf site, Hf(5) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(4), one N(6), one O(1), and one O(2) atom. In the sixth Hf site, Hf(6) is bonded to one N(1), one N(2), one N(4), one N(6), one O(1), and one O(2) atom to form distorted HfN4O2 octahedra that share  a cornercorner with one Mg(1)N3O tetrahedra,  a cornercorner with one Hf(4)N3O tetrahedra, and edges with three equivalent Hf(1)N4O2 octahedra. In the seventh Hf site, Hf(7) is bonded in a 6-coordinate geometry to one N(2), one N(5), one N(6), one N(8), one O(1), and one O(3) atom. In the eighth Hf site, Hf(8) is bonded to one N(3), one N(7), one N(8), and one O(4) atom to form HfN3O tetrahedra that share corners with three equivalent Mg(1)N3O tetrahedra and corners with three equivalent Hf(4)N3O tetrahedra. There are eight inequivalent N sites. In the first N site, N(1) is bonded to one Mg(1), one Hf(1), one Hf(5), and one Hf(6) atom to form NHf3Mg tetrahedra that share corners with three equivalent N(4)Hf4 tetrahedra,  a cornercorner with one N(6)Hf5 trigonal bipyramid, and  an edgeedge with one N(6)Hf5 trigonal bipyramid. In the second N site, N(2) is bonded in a 6-coordinate geometry to one Hf(1), one Hf(2), one Hf(3), one Hf(5), one Hf(6), and one Hf(7) atom. In the third N site, N(3) is bonded in a trigonal planar geometry to one Mg(1), one Hf(4), and one Hf(8) atom. In the fourth N site, N(4) is bonded to one Hf(1), one Hf(4), one Hf(5), and one Hf(6) atom to form NHf4 tetrahedra that share corners with three equivalent N(1)Hf3Mg tetrahedra,  a cornercorner with one N(6)Hf5 trigonal bipyramid, and  an edgeedge with one N(6)Hf5 trigonal bipyramid. In the fifth N site, N(5) is bonded in a trigonal non-coplanar geometry to one Hf(2), one Hf(3), and one Hf(7) atom. In the sixth N site, N(6) is bonded to one Hf(1), one Hf(3), one Hf(5), one Hf(6), and one Hf(7) atom to form distorted NHf5 trigonal bipyramids that share  a cornercorner with one N(1)Hf3Mg tetrahedra,  a cornercorner with one N(4)Hf4 tetrahedra, corners with two equivalent N(8)Hf4 tetrahedra,  an edgeedge with one N(1)Hf3Mg tetrahedra, and  an edgeedge with one N(4)Hf4 tetrahedra. In the seventh N site, N(7) is bonded in a trigonal planar geometry to one Mg(1), one Hf(4), and one Hf(8) atom. In the eighth N site, N(8) is bonded to one Hf(2), one Hf(3), one Hf(7), and one Hf(8) atom to form corner-sharing NHf4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Hf(1), one Hf(5), one Hf(6), and one Hf(7) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Hf(1), one Hf(5), and one Hf(6) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Hf(2), one Hf(3), and one Hf(7) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1), one Hf(4), and one Hf(8) atom. is represented by the CIF card [CIF]
data_Hf8Mg(N2O)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.764
_cell_length_b   5.886
_cell_length_c   10.912
_cell_angle_alpha   90.563
_cell_angle_beta   72.519
_cell_angle_gamma   58.206
_symmetry_Int_Tables_number   1
_cell_volume   293.626
_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
  Hf  Hf0  1  0.177  0.315  0.284  1.0
  Hf  Hf1  1  0.008  0.935  0.946  1.0
  Hf  Hf2  1  0.336  0.293  0.996  1.0
  Hf  Hf3  1  0.620  0.407  0.566  1.0
  Hf  Hf4  1  0.497  0.667  0.302  1.0
  Hf  Hf5  1  0.852  0.966  0.240  1.0
  Hf  Hf6  1  0.663  0.601  0.999  1.0
  Hf  Hf7  1  0.859  0.795  0.682  1.0
  Mg  Mg8  1  0.281  0.089  0.572  1.0
  N  N9  1  0.460  0.016  0.367  1.0
  N  N10  1  0.586  0.237  0.122  1.0
  N  N11  1  0.240  0.768  0.603  1.0
  N  N12  1  0.779  0.317  0.363  1.0
  N  N13  1  0.398  0.569  0.915  1.0
  N  N14  1  0.905  0.563  0.148  1.0
  N  N15  1  0.903  0.458  0.610  1.0
  N  N16  1  0.722  0.871  0.890  1.0
  O  O17  1  0.305  0.917  0.160  1.0
  O  O18  1  0.110  0.680  0.343  1.0
  O  O19  1  0.071  0.236  0.908  1.0
  O  O20  1  0.559  0.116  0.634  1.0
[/CIF]
.
The material described by MgHf8(N2O)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one N(1), one N(3), one N(7), and one O(4) atom to form MgN3O tetrahedra that share  a cornercorner with one Hf(1)N4O2 octahedra,  a cornercorner with one Hf(6)N4O2 octahedra, corners with three equivalent Hf(4)N3O tetrahedra, and corners with three equivalent Hf(8)N3O tetrahedra. The corner-sharing octahedral tilt angles range from 49-67°. There are eight inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one N(1), one N(2), one N(4), one N(6), one O(1), and one O(2) atom to form distorted HfN4O2 octahedra that share  a cornercorner with one Mg(1)N3O tetrahedra,  a cornercorner with one Hf(4)N3O tetrahedra, and edges with three equivalent Hf(6)N4O2 octahedra. In the second Hf site, Hf(2) is bonded in a distorted see-saw-like geometry to one N(2), one N(5), one N(8), and one O(3) atom. In the third Hf site, Hf(3) is bonded in a 5-coordinate geometry to one N(2), one N(5), one N(6), one N(8), and one O(3) atom. In the fourth Hf site, Hf(4) is bonded to one N(3), one N(4), one N(7), and one O(4) atom to form HfN3O tetrahedra that share  a cornercorner with one Hf(1)N4O2 octahedra,  a cornercorner with one Hf(6)N4O2 octahedra, corners with three equivalent Mg(1)N3O tetrahedra, and corners with three equivalent Hf(8)N3O tetrahedra. The corner-sharing octahedral tilt angles range from 55-69°. In the fifth Hf site, Hf(5) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(4), one N(6), one O(1), and one O(2) atom. In the sixth Hf site, Hf(6) is bonded to one N(1), one N(2), one N(4), one N(6), one O(1), and one O(2) atom to form distorted HfN4O2 octahedra that share  a cornercorner with one Mg(1)N3O tetrahedra,  a cornercorner with one Hf(4)N3O tetrahedra, and edges with three equivalent Hf(1)N4O2 octahedra. In the seventh Hf site, Hf(7) is bonded in a 6-coordinate geometry to one N(2), one N(5), one N(6), one N(8), one O(1), and one O(3) atom. In the eighth Hf site, Hf(8) is bonded to one N(3), one N(7), one N(8), and one O(4) atom to form HfN3O tetrahedra that share corners with three equivalent Mg(1)N3O tetrahedra and corners with three equivalent Hf(4)N3O tetrahedra. There are eight inequivalent N sites. In the first N site, N(1) is bonded to one Mg(1), one Hf(1), one Hf(5), and one Hf(6) atom to form NHf3Mg tetrahedra that share corners with three equivalent N(4)Hf4 tetrahedra,  a cornercorner with one N(6)Hf5 trigonal bipyramid, and  an edgeedge with one N(6)Hf5 trigonal bipyramid. In the second N site, N(2) is bonded in a 6-coordinate geometry to one Hf(1), one Hf(2), one Hf(3), one Hf(5), one Hf(6), and one Hf(7) atom. In the third N site, N(3) is bonded in a trigonal planar geometry to one Mg(1), one Hf(4), and one Hf(8) atom. In the fourth N site, N(4) is bonded to one Hf(1), one Hf(4), one Hf(5), and one Hf(6) atom to form NHf4 tetrahedra that share corners with three equivalent N(1)Hf3Mg tetrahedra,  a cornercorner with one N(6)Hf5 trigonal bipyramid, and  an edgeedge with one N(6)Hf5 trigonal bipyramid. In the fifth N site, N(5) is bonded in a trigonal non-coplanar geometry to one Hf(2), one Hf(3), and one Hf(7) atom. In the sixth N site, N(6) is bonded to one Hf(1), one Hf(3), one Hf(5), one Hf(6), and one Hf(7) atom to form distorted NHf5 trigonal bipyramids that share  a cornercorner with one N(1)Hf3Mg tetrahedra,  a cornercorner with one N(4)Hf4 tetrahedra, corners with two equivalent N(8)Hf4 tetrahedra,  an edgeedge with one N(1)Hf3Mg tetrahedra, and  an edgeedge with one N(4)Hf4 tetrahedra. In the seventh N site, N(7) is bonded in a trigonal planar geometry to one Mg(1), one Hf(4), and one Hf(8) atom. In the eighth N site, N(8) is bonded to one Hf(2), one Hf(3), one Hf(7), and one Hf(8) atom to form corner-sharing NHf4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Hf(1), one Hf(5), one Hf(6), and one Hf(7) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Hf(1), one Hf(5), and one Hf(6) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Hf(2), one Hf(3), and one Hf(7) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1), one Hf(4), and one Hf(8) atom. is represented by the CIF card [CIF]
data_Hf8Mg(N2O)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.764
_cell_length_b   5.886
_cell_length_c   10.912
_cell_angle_alpha   90.563
_cell_angle_beta   72.519
_cell_angle_gamma   58.206
_symmetry_Int_Tables_number   1
_cell_volume   293.626
_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
  Hf  Hf0  1  0.177  0.315  0.284  1.0
  Hf  Hf1  1  0.008  0.935  0.946  1.0
  Hf  Hf2  1  0.336  0.293  0.996  1.0
  Hf  Hf3  1  0.620  0.407  0.566  1.0
  Hf  Hf4  1  0.497  0.667  0.302  1.0
  Hf  Hf5  1  0.852  0.966  0.240  1.0
  Hf  Hf6  1  0.663  0.601  0.999  1.0
  Hf  Hf7  1  0.859  0.795  0.682  1.0
  Mg  Mg8  1  0.281  0.089  0.572  1.0
  N  N9  1  0.460  0.016  0.367  1.0
  N  N10  1  0.586  0.237  0.122  1.0
  N  N11  1  0.240  0.768  0.603  1.0
  N  N12  1  0.779  0.317  0.363  1.0
  N  N13  1  0.398  0.569  0.915  1.0
  N  N14  1  0.905  0.563  0.148  1.0
  N  N15  1  0.903  0.458  0.610  1.0
  N  N16  1  0.722  0.871  0.890  1.0
  O  O17  1  0.305  0.917  0.160  1.0
  O  O18  1  0.110  0.680  0.343  1.0
  O  O19  1  0.071  0.236  0.908  1.0
  O  O20  1  0.559  0.116  0.634  1.0
[/CIF]
.