NbMn2N3 crystallizes in the orthorhombic Cmc2_1 space group. Nb(1) is bonded to two equivalent N(1) and three equivalent N(2) atoms to form NbN5 trigonal bipyramids that share corners with eight equivalent Mn(1)N4 tetrahedra, corners with two equivalent Nb(1)N5 trigonal bipyramids, edges with two equivalent Mn(1)N4 tetrahedra, and edges with two equivalent Nb(1)N5 trigonal bipyramids. Mn(1) is bonded to one N(2) and three equivalent N(1) atoms to form distorted MnN4 tetrahedra that share corners with seven equivalent Mn(1)N4 tetrahedra, corners with four equivalent Nb(1)N5 trigonal bipyramids, and  an edgeedge with one Nb(1)N5 trigonal bipyramid. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 4-coordinate geometry to one Nb(1) and three equivalent Mn(1) atoms. In the second N site, N(2) is bonded to three equivalent Nb(1) and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing NMn2Nb3 trigonal bipyramids.
NbMn2N3 crystallizes in the orthorhombic Cmc2_1 space group. Nb(1) is bonded to two equivalent N(1) and three equivalent N(2) atoms to form NbN5 trigonal bipyramids that share corners with eight equivalent Mn(1)N4 tetrahedra, corners with two equivalent Nb(1)N5 trigonal bipyramids, edges with two equivalent Mn(1)N4 tetrahedra, and edges with two equivalent Nb(1)N5 trigonal bipyramids. Both Nb(1)-N(1) bond lengths are 2.06 Å. There are a spread of Nb(1)-N(2) bond distances ranging from 2.09-2.28 Å. Mn(1) is bonded to one N(2) and three equivalent N(1) atoms to form distorted MnN4 tetrahedra that share corners with seven equivalent Mn(1)N4 tetrahedra, corners with four equivalent Nb(1)N5 trigonal bipyramids, and  an edgeedge with one Nb(1)N5 trigonal bipyramid. The Mn(1)-N(2) bond length is 1.90 Å. There are a spread of Mn(1)-N(1) bond distances ranging from 1.84-1.90 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a 4-coordinate geometry to one Nb(1) and three equivalent Mn(1) atoms. In the second N site, N(2) is bonded to three equivalent Nb(1) and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing NMn2Nb3 trigonal bipyramids.