Ca4ZrN4 crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one N(1), one N(2), one N(3), and one N(4) atom to form distorted CaN4 trigonal pyramids that share  a cornercorner with one Ca(3)N5 square pyramid, corners with three equivalent Ca(4)N5 square pyramids, corners with four equivalent Ca(2)N4 tetrahedra, corners with four equivalent Zr(1)N4 tetrahedra,  an edgeedge with one Ca(4)N5 square pyramid, and edges with two equivalent Ca(3)N5 square pyramids. In the second Ca site, Ca(2) is bonded to two equivalent N(2) and two equivalent N(3) atoms to form distorted CaN4 tetrahedra that share corners with two equivalent Ca(3)N5 square pyramids, corners with two equivalent Ca(4)N5 square pyramids, corners with four equivalent Zr(1)N4 tetrahedra, corners with four equivalent Ca(1)N4 trigonal pyramids, and edges with two equivalent Ca(2)N4 tetrahedra. In the third Ca site, Ca(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form CaN5 square pyramids that share corners with three equivalent Ca(4)N5 square pyramids, corners with two equivalent Ca(2)N4 tetrahedra, corners with three equivalent Zr(1)N4 tetrahedra,  a cornercorner with one Ca(1)N4 trigonal pyramid, edges with two equivalent Ca(3)N5 square pyramids, edges with three equivalent Ca(4)N5 square pyramids,  an edgeedge with one Zr(1)N4 tetrahedra, and edges with two equivalent Ca(1)N4 trigonal pyramids. In the fourth Ca site, Ca(4) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form CaN5 square pyramids that share corners with three equivalent Ca(3)N5 square pyramids,  a cornercorner with one Zr(1)N4 tetrahedra, corners with two equivalent Ca(2)N4 tetrahedra, corners with three equivalent Ca(1)N4 trigonal pyramids, edges with two equivalent Ca(4)N5 square pyramids, edges with three equivalent Ca(3)N5 square pyramids, edges with two equivalent Zr(1)N4 tetrahedra, and  an edgeedge with one Ca(1)N4 trigonal pyramid. Zr(1) is bonded to one N(1), one N(2), one N(3), and one N(4) atom to form ZrN4 tetrahedra that share  a cornercorner with one Ca(4)N5 square pyramid, corners with three equivalent Ca(3)N5 square pyramids, corners with four equivalent Ca(2)N4 tetrahedra, corners with four equivalent Ca(1)N4 trigonal pyramids,  an edgeedge with one Ca(3)N5 square pyramid, and edges with two equivalent Ca(4)N5 square pyramids. There are four inequivalent N sites. In the first N site, N(1) is bonded to one Ca(1), two equivalent Ca(3), two equivalent Ca(4), and one Zr(1) atom to form NCa5Zr octahedra that share corners with two equivalent N(3)Ca5Zr octahedra, corners with two equivalent N(4)Ca5Zr octahedra, corners with two equivalent N(2)Ca3Zr tetrahedra, edges with two equivalent N(1)Ca5Zr octahedra, edges with two equivalent N(3)Ca5Zr octahedra, and edges with four equivalent N(4)Ca5Zr octahedra. The corner-sharing octahedral tilt angles range from 7-18°. In the second N site, N(2) is bonded to one Ca(1), two equivalent Ca(2), and one Zr(1) atom to form distorted NCa3Zr tetrahedra that share corners with two equivalent N(1)Ca5Zr octahedra, corners with two equivalent N(4)Ca5Zr octahedra, corners with six equivalent N(3)Ca5Zr octahedra, and  an edgeedge with one N(2)Ca3Zr tetrahedra. The corner-sharing octahedral tilt angles range from 54-68°. In the third N site, N(3) is bonded to one Ca(1), one Ca(3), one Ca(4), two equivalent Ca(2), and one Zr(1) atom to form NCa5Zr octahedra that share corners with two equivalent N(1)Ca5Zr octahedra, corners with six equivalent N(2)Ca3Zr tetrahedra,  an edgeedge with one N(3)Ca5Zr octahedra, edges with two equivalent N(1)Ca5Zr octahedra, and edges with three equivalent N(4)Ca5Zr octahedra. The corner-sharing octahedral tilt angles range from 7-10°. In the fourth N site, N(4) is bonded to one Ca(1), two equivalent Ca(3), two equivalent Ca(4), and one Zr(1) atom to form NCa5Zr octahedra that share corners with two equivalent N(1)Ca5Zr octahedra, corners with two equivalent N(2)Ca3Zr tetrahedra, edges with two equivalent N(4)Ca5Zr octahedra, edges with three equivalent N(3)Ca5Zr octahedra, and edges with four equivalent N(1)Ca5Zr octahedra. The corner-sharing octahedral tilt angles range from 9-18°.
Ca4ZrN4 crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one N(1), one N(2), one N(3), and one N(4) atom to form distorted CaN4 trigonal pyramids that share  a cornercorner with one Ca(3)N5 square pyramid, corners with three equivalent Ca(4)N5 square pyramids, corners with four equivalent Ca(2)N4 tetrahedra, corners with four equivalent Zr(1)N4 tetrahedra,  an edgeedge with one Ca(4)N5 square pyramid, and edges with two equivalent Ca(3)N5 square pyramids. The Ca(1)-N(1) bond length is 2.47 Å. The Ca(1)-N(2) bond length is 2.38 Å. The Ca(1)-N(3) bond length is 2.43 Å. The Ca(1)-N(4) bond length is 2.44 Å. In the second Ca site, Ca(2) is bonded to two equivalent N(2) and two equivalent N(3) atoms to form distorted CaN4 tetrahedra that share corners with two equivalent Ca(3)N5 square pyramids, corners with two equivalent Ca(4)N5 square pyramids, corners with four equivalent Zr(1)N4 tetrahedra, corners with four equivalent Ca(1)N4 trigonal pyramids, and edges with two equivalent Ca(2)N4 tetrahedra. There is one shorter (2.38 Å) and one longer (2.39 Å) Ca(2)-N(2) bond length. There is one shorter (2.48 Å) and one longer (2.51 Å) Ca(2)-N(3) bond length. In the third Ca site, Ca(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form CaN5 square pyramids that share corners with three equivalent Ca(4)N5 square pyramids, corners with two equivalent Ca(2)N4 tetrahedra, corners with three equivalent Zr(1)N4 tetrahedra,  a cornercorner with one Ca(1)N4 trigonal pyramid, edges with two equivalent Ca(3)N5 square pyramids, edges with three equivalent Ca(4)N5 square pyramids,  an edgeedge with one Zr(1)N4 tetrahedra, and edges with two equivalent Ca(1)N4 trigonal pyramids. The Ca(3)-N(3) bond length is 2.58 Å. There is one shorter (2.49 Å) and one longer (2.53 Å) Ca(3)-N(1) bond length. There is one shorter (2.46 Å) and one longer (2.53 Å) Ca(3)-N(4) bond length. In the fourth Ca site, Ca(4) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form CaN5 square pyramids that share corners with three equivalent Ca(3)N5 square pyramids,  a cornercorner with one Zr(1)N4 tetrahedra, corners with two equivalent Ca(2)N4 tetrahedra, corners with three equivalent Ca(1)N4 trigonal pyramids, edges with two equivalent Ca(4)N5 square pyramids, edges with three equivalent Ca(3)N5 square pyramids, edges with two equivalent Zr(1)N4 tetrahedra, and  an edgeedge with one Ca(1)N4 trigonal pyramid. The Ca(4)-N(3) bond length is 2.50 Å. There is one shorter (2.52 Å) and one longer (2.53 Å) Ca(4)-N(1) bond length. There is one shorter (2.47 Å) and one longer (2.64 Å) Ca(4)-N(4) bond length. Zr(1) is bonded to one N(1), one N(2), one N(3), and one N(4) atom to form ZrN4 tetrahedra that share  a cornercorner with one Ca(4)N5 square pyramid, corners with three equivalent Ca(3)N5 square pyramids, corners with four equivalent Ca(2)N4 tetrahedra, corners with four equivalent Ca(1)N4 trigonal pyramids,  an edgeedge with one Ca(3)N5 square pyramid, and edges with two equivalent Ca(4)N5 square pyramids. The Zr(1)-N(1) bond length is 2.11 Å. The Zr(1)-N(2) bond length is 2.06 Å. The Zr(1)-N(3) bond length is 2.10 Å. The Zr(1)-N(4) bond length is 2.11 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded to one Ca(1), two equivalent Ca(3), two equivalent Ca(4), and one Zr(1) atom to form NCa5Zr octahedra that share corners with two equivalent N(3)Ca5Zr octahedra, corners with two equivalent N(4)Ca5Zr octahedra, corners with two equivalent N(2)Ca3Zr tetrahedra, edges with two equivalent N(1)Ca5Zr octahedra, edges with two equivalent N(3)Ca5Zr octahedra, and edges with four equivalent N(4)Ca5Zr octahedra. The corner-sharing octahedral tilt angles range from 7-18°. In the second N site, N(2) is bonded to one Ca(1), two equivalent Ca(2), and one Zr(1) atom to form distorted NCa3Zr tetrahedra that share corners with two equivalent N(1)Ca5Zr octahedra, corners with two equivalent N(4)Ca5Zr octahedra, corners with six equivalent N(3)Ca5Zr octahedra, and  an edgeedge with one N(2)Ca3Zr tetrahedra. The corner-sharing octahedral tilt angles range from 54-68°. In the third N site, N(3) is bonded to one Ca(1), one Ca(3), one Ca(4), two equivalent Ca(2), and one Zr(1) atom to form NCa5Zr octahedra that share corners with two equivalent N(1)Ca5Zr octahedra, corners with six equivalent N(2)Ca3Zr tetrahedra,  an edgeedge with one N(3)Ca5Zr octahedra, edges with two equivalent N(1)Ca5Zr octahedra, and edges with three equivalent N(4)Ca5Zr octahedra. The corner-sharing octahedral tilt angles range from 7-10°. In the fourth N site, N(4) is bonded to one Ca(1), two equivalent Ca(3), two equivalent Ca(4), and one Zr(1) atom to form NCa5Zr octahedra that share corners with two equivalent N(1)Ca5Zr octahedra, corners with two equivalent N(2)Ca3Zr tetrahedra, edges with two equivalent N(4)Ca5Zr octahedra, edges with three equivalent N(3)Ca5Zr octahedra, and edges with four equivalent N(1)Ca5Zr octahedra. The corner-sharing octahedral tilt angles range from 9-18°.