Materials Data on Ca11AlSb9 by Materials Project

Abstract

Ca11AlSb9 crystallizes in the orthorhombic Iba2 space group. The structure is three-dimensional. there are six inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to seven Sb+2.78- atoms to form distorted CaSb7 pentagonal bipyramids that share corners with six CaSb6 octahedra, corners with two equivalent CaSb7 pentagonal bipyramids, a cornercorner with one AlSb4 tetrahedra, edges with three equivalent CaSb7 pentagonal bipyramids, faces with five CaSb6 octahedra, and a faceface with one AlSb4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–54°. There are a spread of Ca–Sb bond distances ranging from 3.08–3.68 Å. In the second Ca2+ site, Ca2+ is bonded to six Sb+2.78- atoms to form distorted CaSb6 octahedra that share corners with five CaSb6 octahedra, corners with two equivalent CaSb7 pentagonal bipyramids, corners with two equivalent AlSb4 tetrahedra, edges with two equivalent CaSb6 octahedra, faces with two CaSb6 octahedra, and faces with two equivalent CaSb7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 33–56°. There are a spread of Ca–Sb bond distances ranging from 3.05–3.40 Å. In the third Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to five Sb+2.78- atoms. There are a spread of Ca–Sb bond distances ranging from 3.06–3.49 Å. In the fourth Ca2+ site, Ca2+ is bonded to six Sb+2.78- atoms to form CaSb6 octahedra that share corners with six CaSb6 octahedra, corners with four equivalent CaSb7 pentagonal bipyramids, edges with two equivalent CaSb6 octahedra, edges with two equivalent AlSb4 tetrahedra, faces with two equivalent CaSb6 octahedra, and faces with two equivalent CaSb7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–42°. There are a spread of Ca–Sb bond distances ranging from 3.05–3.59 Å. In the fifth Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven Sb+2.78- atoms. There are a spread of Ca–Sb bond distances ranging from 3.07–3.82 Å. In the sixth Ca2+ site, Ca2+ is bonded to six Sb+2.78- atoms to form distorted CaSb6 octahedra that share corners with six CaSb6 octahedra, corners with two equivalent CaSb7 pentagonal bipyramids, a cornercorner with one AlSb4 tetrahedra, edges with three CaSb6 octahedra, an edgeedge with one AlSb4 tetrahedra, a faceface with one CaSb6 octahedra, and faces with two equivalent CaSb7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 33–54°. There are a spread of Ca–Sb bond distances ranging from 3.08–3.39 Å. Al3+ is bonded to four Sb+2.78- atoms to form AlSb4 tetrahedra that share corners with six CaSb6 octahedra, corners with two equivalent CaSb7 pentagonal bipyramids, edges with four CaSb6 octahedra, and faces with two equivalent CaSb7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 45–55°. There are two shorter (2.77 Å) and two longer (2.80 Å) Al–Sb bond lengths. There are five inequivalent Sb+2.78- sites. In the first Sb+2.78- site, Sb+2.78- is bonded in a 8-coordinate geometry to eight Ca2+ atoms. In the second Sb+2.78- site, Sb+2.78- is bonded in a 7-coordinate geometry to seven Ca2+ and one Al3+ atom. In the third Sb+2.78- site, Sb+2.78- is bonded in a 2-coordinate geometry to eight Ca2+ and one Sb+2.78- atom. The Sb–Sb bond length is 2.88 Å. In the fourth Sb+2.78- site, Sb+2.78- is bonded in a 9-coordinate geometry to eight Ca2+ and one Al3+ atom. In the fifth Sb+2.78- site, Sb+2.78- is bonded in a 7-coordinate geometry to seven Ca2+ atoms.