K2Al2O7 crystallizes in the orthorhombic Aea2 space group. K(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Al(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing AlO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent K(1) and one Al(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Al(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Al(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1) and two equivalent Al(1) atoms.
K2Al2O7 crystallizes in the orthorhombic Aea2 space group. K(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. The K(1)-O(4) bond length is 2.93 Å. There is one shorter (2.95 Å) and one longer (3.26 Å) K(1)-O(2) bond length. There is one shorter (2.83 Å) and one longer (3.09 Å) K(1)-O(3) bond length. There are a spread of K(1)-O(1) bond distances ranging from 2.83-3.36 Å. Al(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing AlO4 tetrahedra. The Al(1)-O(1) bond length is 1.72 Å. The Al(1)-O(2) bond length is 1.86 Å. The Al(1)-O(3) bond length is 1.86 Å. The Al(1)-O(4) bond length is 1.72 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent K(1) and one Al(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Al(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one Al(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1) and two equivalent Al(1) atoms.