Materials Data on K2Al2O7 by Materials Project
K2Al2O7 crystallizes in the orthorhombic Aea2 space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to nine O atoms. There are a spread of K–O bond distances ranging from 2.83–3.36 Å. Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. There is two shorter (1.72 Å) and two longer (1.86 Å) Al–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to four equivalent K and one Al atom. In the second O site, O is bonded in a distorted single-bond geometry to two equivalent K and one Al atom. In the third O site, O is bonded in a distorted single-bond geometry to two equivalent K and one Al atom. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent K and two equivalent Al atoms.