Ca4Bi2O 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 Bi(1) and one O(1) atom. In the second Ca site, Ca(2) is bonded in a linear geometry to four equivalent Bi(1) and two equivalent O(1) atoms. Bi(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.
Ca4Bi2O 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 Bi(1) and one O(1) atom. There is one shorter (3.25 Å) and four longer (3.38 Å) Ca(1)-Bi(1) bond lengths. The Ca(1)-O(1) bond length is 2.69 Å. In the second Ca site, Ca(2) is bonded in a linear geometry to four equivalent Bi(1) and two equivalent O(1) atoms. All Ca(2)-Bi(1) bond lengths are 3.33 Å. Both Ca(2)-O(1) bond lengths are 2.38 Å. Bi(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.