Materials Data on K2Al2Si2O9 by Materials Project

Abstract

K2Al2Si2O9 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 5-coordinate geometry to five O atoms. There are a spread of K–O bond distances ranging from 2.73–3.01 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.82–3.20 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.74–1.77 Å. In the second Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There is two shorter (1.76 Å) and two longer (1.77 Å) Al–O bond length. There are two inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four AlO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four AlO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Al, and one Si atom. In the second O site, O is bonded in a 2-coordinate geometry to one K, one Al, and one Si atom. In the third O site, O is bonded in a 2-coordinate geometry to two K, one Al, and one Si atom. In the fourth O site, O is bonded in a 4-coordinate geometry to two K, one Al, and one Si atom. In the fifth O site, O is bonded in a 2-coordinate geometry to one K, one Al, and one Si atom. In the sixth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Al, and one Si atom. In the seventh O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Al, and one Si atom. In the eighth O site, O is bonded in a 3-coordinate geometry to three K atoms. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Al, and one Si atom.