Materials Data on Al2CrCl8 by Materials Project
CrAl2Cl8 crystallizes in the orthorhombic Pca2_1 space group. The structure is one-dimensional and consists of four CrAl2Cl8 ribbons oriented in the (1, 0, 0) direction. Cr2+ is bonded to six Cl1- atoms to form CrCl6 octahedra that share corners with two AlCl4 tetrahedra and edges with two AlCl4 tetrahedra. There are a spread of Cr–Cl bond distances ranging from 2.41–2.99 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Cl1- atoms to form AlCl4 tetrahedra that share a cornercorner with one CrCl6 octahedra and an edgeedge with one CrCl6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Al–Cl bond distances ranging from 2.11–2.23 Å. In the second Al3+ site, Al3+ is bonded to four Cl1- atoms to form AlCl4 tetrahedra that share a cornercorner with one CrCl6 octahedra and an edgeedge with one CrCl6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Al–Cl bond distances ranging from 2.11–2.23 Å. There are eight inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Al3+ atom. In the second Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Cr2+ and one Al3+ atom. In the third Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Cr2+ and one Al3+ atom. In the fourth Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cr2+ and one Al3+ atom. In the fifth Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cr2+ and one Al3+ atom. In the sixth Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cr2+ and one Al3+ atom. In the seventh Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cr2+ and one Al3+ atom. In the eighth Cl1- site, Cl1- is bonded in a single-bond geometry to one Al3+ atom.