NdCaCrO4 is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4mm space group. Ca(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent O(3) atoms. Nd(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. Cr(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), two equivalent Nd(1), and two equivalent Cr(1) atoms to form distorted OCa2Nd2Cr2 octahedra that share corners with two equivalent O(1)Ca2Nd2Cr2 octahedra, corners with six equivalent O(3)Ca4NdCr octahedra, corners with six equivalent O(2)CaNd4Cr octahedra, edges with two equivalent O(1)Ca2Nd2Cr2 octahedra, faces with two equivalent O(3)Ca4NdCr octahedra, faces with two equivalent O(2)CaNd4Cr octahedra, and faces with four equivalent O(1)Ca2Nd2Cr2 octahedra. The corner-sharing octahedral tilt angles range from 7-53°. In the second O site, O(2) is bonded to one Ca(1), four equivalent Nd(1), and one Cr(1) atom to form distorted OCaNd4Cr octahedra that share  a cornercorner with one O(3)Ca4NdCr octahedra, corners with four equivalent O(2)CaNd4Cr octahedra, corners with twelve equivalent O(1)Ca2Nd2Cr2 octahedra, edges with four equivalent O(3)Ca4NdCr octahedra, edges with four equivalent O(2)CaNd4Cr octahedra, and faces with four equivalent O(1)Ca2Nd2Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the third O site, O(3) is bonded to four equivalent Ca(1), one Nd(1), and one Cr(1) atom to form distorted OCa4NdCr octahedra that share  a cornercorner with one O(2)CaNd4Cr octahedra, corners with four equivalent O(3)Ca4NdCr octahedra, corners with twelve equivalent O(1)Ca2Nd2Cr2 octahedra, edges with four equivalent O(3)Ca4NdCr octahedra, edges with four equivalent O(2)CaNd4Cr octahedra, and faces with four equivalent O(1)Ca2Nd2Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°.
NdCaCrO4 is (La,Ba)CuO4-derived structured and crystallizes in the tetragonal I4mm space group. Ca(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent O(3) atoms. The Ca(1)-O(2) bond length is 2.27 Å. All Ca(1)-O(1) bond lengths are 2.62 Å. All Ca(1)-O(3) bond lengths are 2.76 Å. Nd(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. The Nd(1)-O(3) bond length is 2.27 Å. All Nd(1)-O(1) bond lengths are 2.54 Å. All Nd(1)-O(2) bond lengths are 2.76 Å. Cr(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 7°. The Cr(1)-O(2) bond length is 2.11 Å. The Cr(1)-O(3) bond length is 2.01 Å. All Cr(1)-O(1) bond lengths are 1.94 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1), two equivalent Nd(1), and two equivalent Cr(1) atoms to form distorted OCa2Nd2Cr2 octahedra that share corners with two equivalent O(1)Ca2Nd2Cr2 octahedra, corners with six equivalent O(3)Ca4NdCr octahedra, corners with six equivalent O(2)CaNd4Cr octahedra, edges with two equivalent O(1)Ca2Nd2Cr2 octahedra, faces with two equivalent O(3)Ca4NdCr octahedra, faces with two equivalent O(2)CaNd4Cr octahedra, and faces with four equivalent O(1)Ca2Nd2Cr2 octahedra. The corner-sharing octahedral tilt angles range from 7-53°. In the second O site, O(2) is bonded to one Ca(1), four equivalent Nd(1), and one Cr(1) atom to form distorted OCaNd4Cr octahedra that share  a cornercorner with one O(3)Ca4NdCr octahedra, corners with four equivalent O(2)CaNd4Cr octahedra, corners with twelve equivalent O(1)Ca2Nd2Cr2 octahedra, edges with four equivalent O(3)Ca4NdCr octahedra, edges with four equivalent O(2)CaNd4Cr octahedra, and faces with four equivalent O(1)Ca2Nd2Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the third O site, O(3) is bonded to four equivalent Ca(1), one Nd(1), and one Cr(1) atom to form distorted OCa4NdCr octahedra that share  a cornercorner with one O(2)CaNd4Cr octahedra, corners with four equivalent O(3)Ca4NdCr octahedra, corners with twelve equivalent O(1)Ca2Nd2Cr2 octahedra, edges with four equivalent O(3)Ca4NdCr octahedra, edges with four equivalent O(2)CaNd4Cr octahedra, and faces with four equivalent O(1)Ca2Nd2Cr2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°.