MgHf8(N2O)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a T-shaped geometry to one N(2), one N(6), and one O(1) atom. 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 O(1), and one O(2) atom to form a mixture of distorted edge and corner-sharing HfN3O2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-78°. In the second Hf site, Hf(2) is bonded to one N(3), one N(5), one N(7), one N(8), one O(3), and one O(4) atom to form distorted HfN4O2 pentagonal pyramids that share corners with three equivalent Hf(4)N4O2 octahedra, corners with three equivalent Hf(3)N3O trigonal pyramids, edges with three equivalent Hf(8)N4O2 octahedra, and  a faceface with one Hf(5)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. In the third Hf site, Hf(3) is bonded to one N(5), one N(6), one N(8), and one O(3) atom to form distorted corner-sharing HfN3O trigonal pyramids. The corner-sharing octahedral tilt angles range from 43-64°. In the fourth Hf site, Hf(4) is bonded to one N(1), one N(3), one N(4), one N(7), one O(2), and one O(4) atom to form distorted HfN4O2 octahedra that share corners with three equivalent Hf(8)N4O2 octahedra, corners with three equivalent Hf(2)N4O2 pentagonal pyramids, corners with three equivalent Hf(1)N3O2 trigonal bipyramids, edges with three equivalent Hf(5)N4O2 octahedra, and  a faceface with one Hf(6)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 54-68°. In the fifth Hf site, Hf(5) is bonded to one N(1), one N(3), one N(4), one N(7), one O(2), and one O(4) atom to form distorted HfN4O2 octahedra that share corners with three equivalent Hf(6)N4O2 octahedra, corners with three equivalent Hf(8)N4O2 octahedra, corners with three equivalent Hf(1)N3O2 trigonal bipyramids, edges with three equivalent Hf(4)N4O2 octahedra, and  a faceface with one Hf(2)N4O2 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 45-52°. 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 corners with three equivalent Hf(5)N4O2 octahedra,  a cornercorner with one Hf(1)N3O2 trigonal bipyramid,  a cornercorner with one Hf(3)N3O trigonal pyramid, edges with two equivalent Hf(1)N3O2 trigonal bipyramids, and  a faceface with one Hf(4)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 45-48°. 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(5), one N(7), one N(8), one O(3), and one O(4) atom to form distorted HfN4O2 octahedra that share corners with three equivalent Hf(4)N4O2 octahedra, corners with three equivalent Hf(5)N4O2 octahedra, corners with three equivalent Hf(3)N3O trigonal pyramids, and edges with three equivalent Hf(2)N4O2 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 45-68°. There are eight inequivalent N sites. In the first N site, N(1) is bonded in a distorted see-saw-like geometry to one Hf(1), one Hf(4), one Hf(5), and one Hf(6) atom. In the second N site, N(2) is bonded to one Mg(1), one Hf(1), one Hf(6), and one Hf(7) atom to form NHf3Mg trigonal pyramids that share  a cornercorner with one N(6)Hf3Mg trigonal pyramid,  a cornercorner with one N(8)Hf4 trigonal pyramid,  a cornercorner with one O(3)Hf4 trigonal pyramid, corners with two equivalent N(4)Hf4 trigonal pyramids, edges with two equivalent O(1)Hf3Mg tetrahedra, and  an edgeedge with one N(6)Hf3Mg trigonal pyramid. In the third N site, N(3) is bonded to one Hf(2), one Hf(4), one Hf(5), and one Hf(8) atom to form distorted NHf4 trigonal pyramids that share corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(4)Hf4 trigonal pyramid,  an edgeedge with one N(7)Hf4 trigonal pyramid,  an edgeedge with one N(8)Hf4 trigonal pyramid, and  an edgeedge with one O(4)Hf4 trigonal pyramid. 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 distorted NHf4 trigonal pyramids that share  a cornercorner with one N(6)Hf3Mg trigonal pyramid, corners with two equivalent N(2)Hf3Mg trigonal pyramids, corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one O(1)Hf3Mg tetrahedra, and  an edgeedge with one N(3)Hf4 trigonal pyramid. In the fifth N site, N(5) is bonded in a distorted see-saw-like geometry to one Hf(2), one Hf(3), one Hf(7), and one Hf(8) atom. In the sixth N site, N(6) is bonded to one Mg(1), one Hf(3), one Hf(6), and one Hf(7) atom to form NHf3Mg trigonal pyramids that share corners with three equivalent O(1)Hf3Mg tetrahedra,  a cornercorner with one N(2)Hf3Mg trigonal pyramid,  a cornercorner with one N(4)Hf4 trigonal pyramid, corners with two equivalent N(8)Hf4 trigonal pyramids,  an edgeedge with one N(2)Hf3Mg trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. In the seventh N site, N(7) is bonded to one Hf(2), one Hf(4), one Hf(5), and one Hf(8) atom to form distorted NHf4 trigonal pyramids that share corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent N(4)Hf4 trigonal pyramids, corners with two equivalent N(8)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid,  an edgeedge with one O(3)Hf4 trigonal pyramid, and  an edgeedge with one O(4)Hf4 trigonal pyramid. 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 distorted NHf4 trigonal pyramids that share  a cornercorner with one O(1)Hf3Mg tetrahedra,  a cornercorner with one N(2)Hf3Mg trigonal pyramid, corners with two equivalent N(6)Hf3Mg trigonal pyramids, corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Hf(1), one Hf(6), and one Hf(7) atom to form OHf3Mg tetrahedra that share  a cornercorner with one N(8)Hf4 trigonal pyramid,  a cornercorner with one O(3)Hf4 trigonal pyramid, corners with three equivalent N(6)Hf3Mg trigonal pyramids,  an edgeedge with one N(4)Hf4 trigonal pyramid, and edges with two equivalent N(2)Hf3Mg trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Hf(1), one Hf(4), one Hf(5), and one Hf(6) atom. In the third O site, O(3) is bonded to one Hf(2), one Hf(3), one Hf(7), and one Hf(8) atom to form distorted OHf4 trigonal pyramids that share  a cornercorner with one O(1)Hf3Mg tetrahedra,  a cornercorner with one N(2)Hf3Mg trigonal pyramid, corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent N(8)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(6)Hf3Mg trigonal pyramid,  an edgeedge with one N(7)Hf4 trigonal pyramid, and  an edgeedge with one N(8)Hf4 trigonal pyramid. In the fourth O site, O(4) is bonded to one Hf(2), one Hf(4), one Hf(5), and one Hf(8) atom to form distorted OHf4 trigonal pyramids that share corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent N(4)Hf4 trigonal pyramids, corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent N(8)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid, and  an edgeedge with one N(7)Hf4 trigonal pyramid.
MgHf8(N2O)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a T-shaped geometry to one N(2), one N(6), and one O(1) atom. The Mg(1)-N(2) bond length is 2.07 Å. The Mg(1)-N(6) bond length is 2.10 Å. The Mg(1)-O(1) bond length is 2.11 Å. 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 O(1), and one O(2) atom to form a mixture of distorted edge and corner-sharing HfN3O2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-78°. The Hf(1)-N(1) bond length is 2.06 Å. The Hf(1)-N(2) bond length is 2.10 Å. The Hf(1)-N(4) bond length is 2.19 Å. The Hf(1)-O(1) bond length is 2.13 Å. The Hf(1)-O(2) bond length is 2.11 Å. In the second Hf site, Hf(2) is bonded to one N(3), one N(5), one N(7), one N(8), one O(3), and one O(4) atom to form distorted HfN4O2 pentagonal pyramids that share corners with three equivalent Hf(4)N4O2 octahedra, corners with three equivalent Hf(3)N3O trigonal pyramids, edges with three equivalent Hf(8)N4O2 octahedra, and  a faceface with one Hf(5)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. The Hf(2)-N(3) bond length is 2.21 Å. The Hf(2)-N(5) bond length is 2.14 Å. The Hf(2)-N(7) bond length is 2.23 Å. The Hf(2)-N(8) bond length is 2.08 Å. The Hf(2)-O(3) bond length is 2.19 Å. The Hf(2)-O(4) bond length is 2.43 Å. In the third Hf site, Hf(3) is bonded to one N(5), one N(6), one N(8), and one O(3) atom to form distorted corner-sharing HfN3O trigonal pyramids. The corner-sharing octahedral tilt angles range from 43-64°. The Hf(3)-N(5) bond length is 2.13 Å. The Hf(3)-N(6) bond length is 2.08 Å. The Hf(3)-N(8) bond length is 2.08 Å. The Hf(3)-O(3) bond length is 2.12 Å. In the fourth Hf site, Hf(4) is bonded to one N(1), one N(3), one N(4), one N(7), one O(2), and one O(4) atom to form distorted HfN4O2 octahedra that share corners with three equivalent Hf(8)N4O2 octahedra, corners with three equivalent Hf(2)N4O2 pentagonal pyramids, corners with three equivalent Hf(1)N3O2 trigonal bipyramids, edges with three equivalent Hf(5)N4O2 octahedra, and  a faceface with one Hf(6)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 54-68°. The Hf(4)-N(1) bond length is 2.28 Å. The Hf(4)-N(3) bond length is 2.04 Å. The Hf(4)-N(4) bond length is 2.16 Å. The Hf(4)-N(7) bond length is 2.11 Å. The Hf(4)-O(2) bond length is 2.53 Å. The Hf(4)-O(4) bond length is 2.23 Å. In the fifth Hf site, Hf(5) is bonded to one N(1), one N(3), one N(4), one N(7), one O(2), and one O(4) atom to form distorted HfN4O2 octahedra that share corners with three equivalent Hf(6)N4O2 octahedra, corners with three equivalent Hf(8)N4O2 octahedra, corners with three equivalent Hf(1)N3O2 trigonal bipyramids, edges with three equivalent Hf(4)N4O2 octahedra, and  a faceface with one Hf(2)N4O2 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 45-52°. The Hf(5)-N(1) bond length is 2.12 Å. The Hf(5)-N(3) bond length is 2.27 Å. The Hf(5)-N(4) bond length is 2.11 Å. The Hf(5)-N(7) bond length is 2.30 Å. The Hf(5)-O(2) bond length is 2.12 Å. The Hf(5)-O(4) bond length is 2.22 Å. 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 corners with three equivalent Hf(5)N4O2 octahedra,  a cornercorner with one Hf(1)N3O2 trigonal bipyramid,  a cornercorner with one Hf(3)N3O trigonal pyramid, edges with two equivalent Hf(1)N3O2 trigonal bipyramids, and  a faceface with one Hf(4)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 45-48°. The Hf(6)-N(1) bond length is 2.21 Å. The Hf(6)-N(2) bond length is 2.05 Å. The Hf(6)-N(4) bond length is 2.36 Å. The Hf(6)-N(6) bond length is 2.08 Å. The Hf(6)-O(1) bond length is 2.09 Å. The Hf(6)-O(2) bond length is 2.25 Å. 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. The Hf(7)-N(2) bond length is 2.16 Å. The Hf(7)-N(5) bond length is 2.28 Å. The Hf(7)-N(6) bond length is 2.26 Å. The Hf(7)-N(8) bond length is 2.16 Å. The Hf(7)-O(1) bond length is 2.16 Å. The Hf(7)-O(3) bond length is 2.42 Å. In the eighth Hf site, Hf(8) is bonded to one N(3), one N(5), one N(7), one N(8), one O(3), and one O(4) atom to form distorted HfN4O2 octahedra that share corners with three equivalent Hf(4)N4O2 octahedra, corners with three equivalent Hf(5)N4O2 octahedra, corners with three equivalent Hf(3)N3O trigonal pyramids, and edges with three equivalent Hf(2)N4O2 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 45-68°. The Hf(8)-N(3) bond length is 2.16 Å. The Hf(8)-N(5) bond length is 2.29 Å. The Hf(8)-N(7) bond length is 2.13 Å. The Hf(8)-N(8) bond length is 2.27 Å. The Hf(8)-O(3) bond length is 2.17 Å. The Hf(8)-O(4) bond length is 2.12 Å. There are eight inequivalent N sites. In the first N site, N(1) is bonded in a distorted see-saw-like geometry to one Hf(1), one Hf(4), one Hf(5), and one Hf(6) atom. In the second N site, N(2) is bonded to one Mg(1), one Hf(1), one Hf(6), and one Hf(7) atom to form NHf3Mg trigonal pyramids that share  a cornercorner with one N(6)Hf3Mg trigonal pyramid,  a cornercorner with one N(8)Hf4 trigonal pyramid,  a cornercorner with one O(3)Hf4 trigonal pyramid, corners with two equivalent N(4)Hf4 trigonal pyramids, edges with two equivalent O(1)Hf3Mg tetrahedra, and  an edgeedge with one N(6)Hf3Mg trigonal pyramid. In the third N site, N(3) is bonded to one Hf(2), one Hf(4), one Hf(5), and one Hf(8) atom to form distorted NHf4 trigonal pyramids that share corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(4)Hf4 trigonal pyramid,  an edgeedge with one N(7)Hf4 trigonal pyramid,  an edgeedge with one N(8)Hf4 trigonal pyramid, and  an edgeedge with one O(4)Hf4 trigonal pyramid. 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 distorted NHf4 trigonal pyramids that share  a cornercorner with one N(6)Hf3Mg trigonal pyramid, corners with two equivalent N(2)Hf3Mg trigonal pyramids, corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one O(1)Hf3Mg tetrahedra, and  an edgeedge with one N(3)Hf4 trigonal pyramid. In the fifth N site, N(5) is bonded in a distorted see-saw-like geometry to one Hf(2), one Hf(3), one Hf(7), and one Hf(8) atom. In the sixth N site, N(6) is bonded to one Mg(1), one Hf(3), one Hf(6), and one Hf(7) atom to form NHf3Mg trigonal pyramids that share corners with three equivalent O(1)Hf3Mg tetrahedra,  a cornercorner with one N(2)Hf3Mg trigonal pyramid,  a cornercorner with one N(4)Hf4 trigonal pyramid, corners with two equivalent N(8)Hf4 trigonal pyramids,  an edgeedge with one N(2)Hf3Mg trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. In the seventh N site, N(7) is bonded to one Hf(2), one Hf(4), one Hf(5), and one Hf(8) atom to form distorted NHf4 trigonal pyramids that share corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent N(4)Hf4 trigonal pyramids, corners with two equivalent N(8)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid,  an edgeedge with one O(3)Hf4 trigonal pyramid, and  an edgeedge with one O(4)Hf4 trigonal pyramid. 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 distorted NHf4 trigonal pyramids that share  a cornercorner with one O(1)Hf3Mg tetrahedra,  a cornercorner with one N(2)Hf3Mg trigonal pyramid, corners with two equivalent N(6)Hf3Mg trigonal pyramids, corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid, and  an edgeedge with one O(3)Hf4 trigonal pyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Hf(1), one Hf(6), and one Hf(7) atom to form OHf3Mg tetrahedra that share  a cornercorner with one N(8)Hf4 trigonal pyramid,  a cornercorner with one O(3)Hf4 trigonal pyramid, corners with three equivalent N(6)Hf3Mg trigonal pyramids,  an edgeedge with one N(4)Hf4 trigonal pyramid, and edges with two equivalent N(2)Hf3Mg trigonal pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Hf(1), one Hf(4), one Hf(5), and one Hf(6) atom. In the third O site, O(3) is bonded to one Hf(2), one Hf(3), one Hf(7), and one Hf(8) atom to form distorted OHf4 trigonal pyramids that share  a cornercorner with one O(1)Hf3Mg tetrahedra,  a cornercorner with one N(2)Hf3Mg trigonal pyramid, corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent N(8)Hf4 trigonal pyramids, corners with two equivalent O(4)Hf4 trigonal pyramids,  an edgeedge with one N(6)Hf3Mg trigonal pyramid,  an edgeedge with one N(7)Hf4 trigonal pyramid, and  an edgeedge with one N(8)Hf4 trigonal pyramid. In the fourth O site, O(4) is bonded to one Hf(2), one Hf(4), one Hf(5), and one Hf(8) atom to form distorted OHf4 trigonal pyramids that share corners with two equivalent N(3)Hf4 trigonal pyramids, corners with two equivalent N(4)Hf4 trigonal pyramids, corners with two equivalent N(7)Hf4 trigonal pyramids, corners with two equivalent N(8)Hf4 trigonal pyramids, corners with two equivalent O(3)Hf4 trigonal pyramids,  an edgeedge with one N(3)Hf4 trigonal pyramid, and  an edgeedge with one N(7)Hf4 trigonal pyramid.