Materials Data on Ca4Tl2CO9 by Materials Project

Abstract

Ca4Tl2CO3O6 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to seven O2- atoms to form CaO7 pentagonal bipyramids that share corners with four equivalent CaO7 pentagonal bipyramids, edges with four equivalent TlO6 octahedra, and an edgeedge with one CaO7 pentagonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.44–2.63 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.57 Å. Tl3+ is bonded to six O2- atoms to form TlO6 octahedra that share corners with four equivalent TlO6 octahedra, edges with four equivalent TlO6 octahedra, and edges with four equivalent CaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 3°. There are a spread of Tl–O bond distances ranging from 2.14–2.45 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.29 Å) and one longer (1.30 Å) C–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ca2+ and one Tl3+ atom to form OCa4Tl square pyramids that share corners with four equivalent OCa4Tl square pyramids, a cornercorner with one OCa4Tl trigonal bipyramid, edges with four equivalent OCa2Tl4 octahedra, and edges with four equivalent OCa4Tl trigonal bipyramids. In the second O2- site, O2- is bonded to four Ca2+ and one Tl3+ atom to form distorted OCa4Tl trigonal bipyramids that share a cornercorner with one OCa4Tl square pyramid, corners with four equivalent OCa4Tl trigonal bipyramids, edges with four equivalent OCa2Tl4 octahedra, and edges with four equivalent OCa4Tl square pyramids. In the third O2- site, O2- is bonded to two Ca2+ and four equivalent Tl3+ atoms to form OCa2Tl4 octahedra that share corners with four equivalent OCa2Tl4 octahedra, edges with four equivalent OCa2Tl4 octahedra, edges with four equivalent OCa4Tl square pyramids, and edges with four equivalent OCa4Tl trigonal bipyramids. The corner-sharing octahedral tilt angles are 3°. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ca2+ and one C4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one C4+ atom.