Materials Data on Ca4As2O by Materials Project
Ca4As2O is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to five equivalent As3- and one O2- atom. There are one shorter (2.96 Å) and four longer (3.27 Å) Ca–As bond lengths. The Ca–O bond length is 2.66 Å. In the second Ca2+ site, Ca2+ is bonded in a distorted linear geometry to four equivalent As3- and two equivalent O2- atoms. All Ca–As bond lengths are 3.12 Å. Both Ca–O bond lengths are 2.28 Å. As3- is bonded in a 9-coordinate geometry to nine Ca2+ atoms. O2- is bonded to six Ca2+ atoms to form corner-sharing OCa6 octahedra. The corner-sharing octahedral tilt angles are 0°.