Materials Data on K3Al2(AsO4)3 by Materials Project
K3Al2(AsO4)3 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.71–3.08 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.68–3.36 Å. In the third K1+ site, K1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 2.63–2.86 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four AsO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.76–1.78 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four AsO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.76–1.78 Å. There are three inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with three AlO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.68–1.74 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with three AlO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.67–1.73 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two AlO4 tetrahedra. There are a spread of As–O bond distances ranging from 1.69–1.77 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three K1+ and one As5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one As5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+, one Al3+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three K1+ and one As5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Al3+ and one As5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+, one Al3+, and one As5+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one K1+, one Al3+, and one As5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one As5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one As5+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one As5+ atom.