MgNi5N4 crystallizes in the orthorhombic Pmmn space group. Mg(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted MgN4 tetrahedra that share corners with four equivalent Ni(2)N4 trigonal pyramids. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted trigonal planar geometry to one N(1) and two equivalent N(2) atoms. In the second Ni site, Ni(2) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted NiN4 trigonal pyramids that share corners with four equivalent Mg(1)N4 tetrahedra. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Mg(1), one Ni(2), and two equivalent Ni(1) atoms to form NMgNi3 tetrahedra that share corners with eight equivalent N(2)MgNi5 octahedra and corners with two equivalent N(1)MgNi3 tetrahedra. The corner-sharing octahedral tilt angles range from 43-80°. In the second N site, N(2) is bonded to one Mg(1), one Ni(2), and four equivalent Ni(1) atoms to form NMgNi5 octahedra that share corners with two equivalent N(2)MgNi5 octahedra, corners with eight equivalent N(1)MgNi3 tetrahedra, and edges with two equivalent N(2)MgNi5 octahedra. The corner-sharing octahedral tilt angles range from 30-54°.
MgNi5N4 crystallizes in the orthorhombic Pmmn space group. Mg(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted MgN4 tetrahedra that share corners with four equivalent Ni(2)N4 trigonal pyramids. Both Mg(1)-N(1) bond lengths are 2.05 Å. Both Mg(1)-N(2) bond lengths are 2.24 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a distorted trigonal planar geometry to one N(1) and two equivalent N(2) atoms. The Ni(1)-N(1) bond length is 1.82 Å. There is one shorter (1.94 Å) and one longer (1.97 Å) Ni(1)-N(2) bond length. In the second Ni site, Ni(2) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted NiN4 trigonal pyramids that share corners with four equivalent Mg(1)N4 tetrahedra. Both Ni(2)-N(1) bond lengths are 1.92 Å. Both Ni(2)-N(2) bond lengths are 1.96 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Mg(1), one Ni(2), and two equivalent Ni(1) atoms to form NMgNi3 tetrahedra that share corners with eight equivalent N(2)MgNi5 octahedra and corners with two equivalent N(1)MgNi3 tetrahedra. The corner-sharing octahedral tilt angles range from 43-80°. In the second N site, N(2) is bonded to one Mg(1), one Ni(2), and four equivalent Ni(1) atoms to form NMgNi5 octahedra that share corners with two equivalent N(2)MgNi5 octahedra, corners with eight equivalent N(1)MgNi3 tetrahedra, and edges with two equivalent N(2)MgNi5 octahedra. The corner-sharing octahedral tilt angles range from 30-54°.