Mg3(InN2)2 is Aluminum carbonitride-like structured and crystallizes in the monoclinic C2/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to two equivalent N(2) and three equivalent N(1) atoms. In the second Mg site, Mg(2) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form MgN4 tetrahedra that share corners with eight equivalent In(1)N4 tetrahedra. In(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted InN4 tetrahedra that share corners with two equivalent In(1)N4 tetrahedra, corners with four equivalent Mg(2)N4 tetrahedra, and  an edgeedge with one In(1)N4 tetrahedra. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Mg(2), three equivalent Mg(1), and two equivalent In(1) atoms to form a mixture of distorted corner and edge-sharing NMg4In2 pentagonal pyramids. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent In(1) atoms.
Mg3(InN2)2 is Aluminum carbonitride-like structured and crystallizes in the monoclinic C2/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to two equivalent N(2) and three equivalent N(1) atoms. There is one shorter (2.15 Å) and one longer (2.68 Å) Mg(1)-N(2) bond length. There are a spread of Mg(1)-N(1) bond distances ranging from 2.16-2.33 Å. In the second Mg site, Mg(2) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form MgN4 tetrahedra that share corners with eight equivalent In(1)N4 tetrahedra. Both Mg(2)-N(1) bond lengths are 2.19 Å. Both Mg(2)-N(2) bond lengths are 2.10 Å. In(1) is bonded to two equivalent N(1) and two equivalent N(2) atoms to form distorted InN4 tetrahedra that share corners with two equivalent In(1)N4 tetrahedra, corners with four equivalent Mg(2)N4 tetrahedra, and  an edgeedge with one In(1)N4 tetrahedra. There is one shorter (2.29 Å) and one longer (2.33 Å) In(1)-N(1) bond length. There is one shorter (2.17 Å) and one longer (2.18 Å) In(1)-N(2) bond length. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Mg(2), three equivalent Mg(1), and two equivalent In(1) atoms to form a mixture of distorted corner and edge-sharing NMg4In2 pentagonal pyramids. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent In(1) atoms.