MgNb4(NO)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 6-coordinate geometry to one N(3), one N(4), one O(1), one O(3), and two equivalent O(2) atoms. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one N(1), one N(2), one N(4), one O(2), and two equivalent O(1) atoms. In the second Nb site, Nb(2) is bonded to one N(1), one N(2), two equivalent N(3), one O(2), and one O(4) atom to form NbN4O2 octahedra that share corners with two equivalent Nb(2)N4O2 octahedra,  a cornercorner with one Nb(4)N3O3 pentagonal pyramid, edges with two equivalent Nb(3)N4O2 octahedra, and edges with two equivalent Nb(4)N3O3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 30°. In the third Nb site, Nb(3) is bonded to one N(3), one N(4), two equivalent N(2), one O(1), and one O(3) atom to form distorted NbN4O2 octahedra that share corners with two equivalent Nb(3)N4O2 octahedra,  a cornercorner with one Nb(4)N3O3 pentagonal pyramid, edges with two equivalent Nb(2)N4O2 octahedra, and  an edgeedge with one Nb(4)N3O3 pentagonal pyramid. The corner-sharing octahedral tilt angles are 40°. In the fourth Nb site, Nb(4) is bonded to one N(1), one N(3), one N(4), one O(3), and two equivalent O(4) atoms to form distorted NbN3O3 pentagonal pyramids that share  a cornercorner with one Nb(2)N4O2 octahedra,  a cornercorner with one Nb(3)N4O2 octahedra, corners with two equivalent Nb(4)N3O3 pentagonal pyramids,  an edgeedge with one Nb(3)N4O2 octahedra, and edges with two equivalent Nb(2)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 32-41°. There are four inequivalent N sites. In the first N site, N(1) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the second N site, N(2) is bonded to one Nb(1), one Nb(2), and two equivalent Nb(3) atoms to form corner-sharing NNb4 trigonal pyramids. In the third N site, N(3) is bonded in a 5-coordinate geometry to one Mg(1), one Nb(3), one Nb(4), and two equivalent Nb(2) atoms. In the fourth N site, N(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(1), one Nb(3), and one Nb(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Nb(3), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Mg(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(3), and one Nb(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Nb(2) and two equivalent Nb(4) atoms.
MgNb4(NO)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 6-coordinate geometry to one N(3), one N(4), one O(1), one O(3), and two equivalent O(2) atoms. The Mg(1)-N(3) bond length is 2.66 Å. The Mg(1)-N(4) bond length is 2.39 Å. The Mg(1)-O(1) bond length is 2.29 Å. The Mg(1)-O(3) bond length is 2.06 Å. There is one shorter (2.06 Å) and one longer (2.07 Å) Mg(1)-O(2) bond length. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one N(1), one N(2), one N(4), one O(2), and two equivalent O(1) atoms. The Nb(1)-N(1) bond length is 2.01 Å. The Nb(1)-N(2) bond length is 2.05 Å. The Nb(1)-N(4) bond length is 2.24 Å. The Nb(1)-O(2) bond length is 2.11 Å. There is one shorter (2.00 Å) and one longer (2.10 Å) Nb(1)-O(1) bond length. In the second Nb site, Nb(2) is bonded to one N(1), one N(2), two equivalent N(3), one O(2), and one O(4) atom to form NbN4O2 octahedra that share corners with two equivalent Nb(2)N4O2 octahedra,  a cornercorner with one Nb(4)N3O3 pentagonal pyramid, edges with two equivalent Nb(3)N4O2 octahedra, and edges with two equivalent Nb(4)N3O3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 30°. The Nb(2)-N(1) bond length is 2.04 Å. The Nb(2)-N(2) bond length is 2.22 Å. There is one shorter (2.03 Å) and one longer (2.05 Å) Nb(2)-N(3) bond length. The Nb(2)-O(2) bond length is 2.17 Å. The Nb(2)-O(4) bond length is 2.25 Å. In the third Nb site, Nb(3) is bonded to one N(3), one N(4), two equivalent N(2), one O(1), and one O(3) atom to form distorted NbN4O2 octahedra that share corners with two equivalent Nb(3)N4O2 octahedra,  a cornercorner with one Nb(4)N3O3 pentagonal pyramid, edges with two equivalent Nb(2)N4O2 octahedra, and  an edgeedge with one Nb(4)N3O3 pentagonal pyramid. The corner-sharing octahedral tilt angles are 40°. The Nb(3)-N(3) bond length is 2.23 Å. The Nb(3)-N(4) bond length is 1.93 Å. There is one shorter (2.08 Å) and one longer (2.12 Å) Nb(3)-N(2) bond length. The Nb(3)-O(1) bond length is 2.52 Å. The Nb(3)-O(3) bond length is 2.16 Å. In the fourth Nb site, Nb(4) is bonded to one N(1), one N(3), one N(4), one O(3), and two equivalent O(4) atoms to form distorted NbN3O3 pentagonal pyramids that share  a cornercorner with one Nb(2)N4O2 octahedra,  a cornercorner with one Nb(3)N4O2 octahedra, corners with two equivalent Nb(4)N3O3 pentagonal pyramids,  an edgeedge with one Nb(3)N4O2 octahedra, and edges with two equivalent Nb(2)N4O2 octahedra. The corner-sharing octahedral tilt angles range from 32-41°. The Nb(4)-N(1) bond length is 2.05 Å. The Nb(4)-N(3) bond length is 2.30 Å. The Nb(4)-N(4) bond length is 2.15 Å. The Nb(4)-O(3) bond length is 1.95 Å. There is one shorter (1.95 Å) and one longer (2.19 Å) Nb(4)-O(4) bond length. There are four inequivalent N sites. In the first N site, N(1) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(2), and one Nb(4) atom. In the second N site, N(2) is bonded to one Nb(1), one Nb(2), and two equivalent Nb(3) atoms to form corner-sharing NNb4 trigonal pyramids. In the third N site, N(3) is bonded in a 5-coordinate geometry to one Mg(1), one Nb(3), one Nb(4), and two equivalent Nb(2) atoms. In the fourth N site, N(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Nb(1), one Nb(3), and one Nb(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Nb(3), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Mg(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(3), and one Nb(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Nb(2) and two equivalent Nb(4) atoms.