Materials Data on KAl2Br7 by Materials Project
KAl2Br7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven Br1- atoms. There are a spread of K–Br bond distances ranging from 3.43–3.83 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Br1- atoms to form corner-sharing AlBr4 tetrahedra. There are a spread of Al–Br bond distances ranging from 2.30–2.47 Å. In the second Al3+ site, Al3+ is bonded to four Br1- atoms to form corner-sharing AlBr4 tetrahedra. There are a spread of Al–Br bond distances ranging from 2.30–2.45 Å. There are seven inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted single-bond geometry to one K1+ and one Al3+ atom. In the second Br1- site, Br1- is bonded in a distorted single-bond geometry to one K1+ and one Al3+ atom. In the third Br1- site, Br1- is bonded in a water-like geometry to two Al3+ atoms. In the fourth Br1- site, Br1- is bonded in a distorted single-bond geometry to two equivalent K1+ and one Al3+ atom. In the fifth Br1- site, Br1- is bonded in a distorted single-bond geometry to one K1+ and one Al3+ atom. In the sixth Br1- site, Br1- is bonded in a distorted L-shaped geometry to one K1+ and one Al3+ atom. In the seventh Br1- site, Br1- is bonded in a distorted bent 120 degrees geometry to one K1+ and one Al3+ atom.