Ca4As2O is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to five equivalent As(1) and one O(1) atom. In the second Ca site, Ca(2) is bonded in a distorted linear geometry to four equivalent As(1) and two equivalent O(1) atoms. As(1) is bonded in a 9-coordinate geometry to four equivalent Ca(2) and five equivalent Ca(1) atoms. O(1) is bonded to two equivalent Ca(1) and four equivalent Ca(2) atoms to form corner-sharing OCa6 octahedra. The corner-sharing octahedra are not tilted.
Ca4As2O is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to five equivalent As(1) and one O(1) atom. There is one shorter (2.95 Å) and four longer (3.26 Å) Ca(1)-As(1) bond lengths. The Ca(1)-O(1) bond length is 2.64 Å. In the second Ca site, Ca(2) is bonded in a distorted linear geometry to four equivalent As(1) and two equivalent O(1) atoms. All Ca(2)-As(1) bond lengths are 3.10 Å. Both Ca(2)-O(1) bond lengths are 2.27 Å. As(1) is bonded in a 9-coordinate geometry to four equivalent Ca(2) and five equivalent Ca(1) atoms. O(1) is bonded to two equivalent Ca(1) and four equivalent Ca(2) atoms to form corner-sharing OCa6 octahedra. The corner-sharing octahedra are not tilted.