Ca2MnN3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to two equivalent N(1) and three equivalent N(2) atoms. In the second Ca site, Ca(2) is bonded to two equivalent N(2), two equivalent N(3), and three equivalent N(1) atoms to form distorted CaN7 pentagonal bipyramids that share corners with four equivalent Ca(2)N7 pentagonal bipyramids,  a cornercorner with one Mn(1)N4 tetrahedra, edges with three equivalent Ca(2)N7 pentagonal bipyramids, and edges with four equivalent Mn(1)N4 tetrahedra. Mn(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form MnN4 tetrahedra that share  a cornercorner with one Ca(2)N7 pentagonal bipyramid, corners with two equivalent Mn(1)N4 tetrahedra, and edges with four equivalent Ca(2)N7 pentagonal bipyramids. There are three inequivalent N sites. In the first N site, N(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Ca(2) and two equivalent Mn(1) atoms. In the second N site, N(1) is bonded in a 6-coordinate geometry to two equivalent Ca(1), three equivalent Ca(2), and one Mn(1) atom. In the third N site, N(2) is bonded to two equivalent Ca(2), three equivalent Ca(1), and one Mn(1) atom to form a mixture of distorted corner and edge-sharing NCa5Mn octahedra. The corner-sharing octahedral tilt angles are 13°.
Ca2MnN3 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to two equivalent N(1) and three equivalent N(2) atoms. There is one shorter (2.40 Å) and one longer (2.50 Å) Ca(1)-N(1) bond length. There is one shorter (2.59 Å) and two longer (2.75 Å) Ca(1)-N(2) bond lengths. In the second Ca site, Ca(2) is bonded to two equivalent N(2), two equivalent N(3), and three equivalent N(1) atoms to form distorted CaN7 pentagonal bipyramids that share corners with four equivalent Ca(2)N7 pentagonal bipyramids,  a cornercorner with one Mn(1)N4 tetrahedra, edges with three equivalent Ca(2)N7 pentagonal bipyramids, and edges with four equivalent Mn(1)N4 tetrahedra. There is one shorter (2.39 Å) and one longer (2.54 Å) Ca(2)-N(2) bond length. Both Ca(2)-N(3) bond lengths are 2.55 Å. There is one shorter (2.53 Å) and two longer (2.77 Å) Ca(2)-N(1) bond lengths. Mn(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form MnN4 tetrahedra that share  a cornercorner with one Ca(2)N7 pentagonal bipyramid, corners with two equivalent Mn(1)N4 tetrahedra, and edges with four equivalent Ca(2)N7 pentagonal bipyramids. The Mn(1)-N(1) bond length is 1.75 Å. The Mn(1)-N(2) bond length is 1.77 Å. Both Mn(1)-N(3) bond lengths are 1.77 Å. There are three inequivalent N sites. In the first N site, N(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Ca(2) and two equivalent Mn(1) atoms. In the second N site, N(1) is bonded in a 6-coordinate geometry to two equivalent Ca(1), three equivalent Ca(2), and one Mn(1) atom. In the third N site, N(2) is bonded to two equivalent Ca(2), three equivalent Ca(1), and one Mn(1) atom to form a mixture of distorted corner and edge-sharing NCa5Mn octahedra. The corner-sharing octahedral tilt angles are 13°.