Materials Data on KSnAsO5 by Materials Project
KSnOAsO4 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first 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 2.76–3.15 Å. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.81–3.36 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with two equivalent SnO6 octahedra and corners with four AsO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Sn–O bond distances ranging from 2.02–2.17 Å. In the second Sn4+ site, Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with two equivalent SnO6 octahedra and corners with four AsO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Sn–O bond distances ranging from 2.02–2.16 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four SnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–53°. There is two shorter (1.72 Å) and two longer (1.73 Å) As–O bond length. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four SnO6 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of As–O bond distances ranging from 1.71–1.73 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two K1+ and two Sn4+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two K1+ and two Sn4+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Sn4+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sn4+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Sn4+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Sn4+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Sn4+, and one As5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two K1+, one Sn4+, and one As5+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Sn4+, and one As5+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Sn4+, and one As5+ atom.