Ca5(TiN3)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one N(3), two equivalent N(1), and two equivalent N(2) atoms. In the second Ca site, Ca(2) is bonded to one N(3), two equivalent N(1), and two equivalent N(2) atoms to form distorted CaN5 trigonal bipyramids that share corners with two equivalent Ti(1)N4 tetrahedra, corners with two equivalent Ca(2)N5 trigonal bipyramids, edges with two equivalent Ti(1)N4 tetrahedra, and  an edgeedge with one Ca(2)N5 trigonal bipyramid. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to two equivalent N(1), two equivalent N(2), and two equivalent N(3) atoms. Ti(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form TiN4 tetrahedra that share corners with two equivalent Ca(2)N5 trigonal bipyramids,  an edgeedge with one Ti(1)N4 tetrahedra, and edges with two equivalent Ca(2)N5 trigonal bipyramids. There are three inequivalent N sites. In the first N site, N(2) is bonded in a 6-coordinate geometry to one Ca(3), two equivalent Ca(1), two equivalent Ca(2), and one Ti(1) atom. In the second N site, N(3) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), and two equivalent Ti(1) atoms. In the third N site, N(1) is bonded in a 6-coordinate geometry to one Ca(3), two equivalent Ca(1), two equivalent Ca(2), and one Ti(1) atom.
Ca5(TiN3)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one N(3), two equivalent N(1), and two equivalent N(2) atoms. The Ca(1)-N(3) bond length is 2.99 Å. There is one shorter (2.38 Å) and one longer (2.55 Å) Ca(1)-N(1) bond length. There is one shorter (2.46 Å) and one longer (2.79 Å) Ca(1)-N(2) bond length. In the second Ca site, Ca(2) is bonded to one N(3), two equivalent N(1), and two equivalent N(2) atoms to form distorted CaN5 trigonal bipyramids that share corners with two equivalent Ti(1)N4 tetrahedra, corners with two equivalent Ca(2)N5 trigonal bipyramids, edges with two equivalent Ti(1)N4 tetrahedra, and  an edgeedge with one Ca(2)N5 trigonal bipyramid. The Ca(2)-N(3) bond length is 2.52 Å. There is one shorter (2.40 Å) and one longer (2.61 Å) Ca(2)-N(1) bond length. There is one shorter (2.53 Å) and one longer (2.54 Å) Ca(2)-N(2) bond length. In the third Ca site, Ca(3) is bonded in a 6-coordinate geometry to two equivalent N(1), two equivalent N(2), and two equivalent N(3) atoms. Both Ca(3)-N(1) bond lengths are 2.80 Å. Both Ca(3)-N(2) bond lengths are 2.47 Å. Both Ca(3)-N(3) bond lengths are 2.66 Å. Ti(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form TiN4 tetrahedra that share corners with two equivalent Ca(2)N5 trigonal bipyramids,  an edgeedge with one Ti(1)N4 tetrahedra, and edges with two equivalent Ca(2)N5 trigonal bipyramids. The Ti(1)-N(1) bond length is 1.90 Å. The Ti(1)-N(2) bond length is 1.93 Å. There is one shorter (1.94 Å) and one longer (1.96 Å) Ti(1)-N(3) bond length. There are three inequivalent N sites. In the first N site, N(2) is bonded in a 6-coordinate geometry to one Ca(3), two equivalent Ca(1), two equivalent Ca(2), and one Ti(1) atom. In the second N site, N(3) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(2), one Ca(3), and two equivalent Ti(1) atoms. In the third N site, N(1) is bonded in a 6-coordinate geometry to one Ca(3), two equivalent Ca(1), two equivalent Ca(2), and one Ti(1) atom.