Materials Data on KTaGeO5 by Materials Project
KTaGeO5 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 2.75–3.23 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 2.74–3.32 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–40°. There are a spread of Ta–O bond distances ranging from 1.95–2.05 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–40°. There are a spread of Ta–O bond distances ranging from 1.94–2.05 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four TaO6 octahedra. The corner-sharing octahedra tilt angles range from 49–51°. There is one shorter (1.76 Å) and three longer (1.77 Å) Ge–O bond length. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four TaO6 octahedra. The corner-sharing octahedra tilt angles range from 43–54°. There are a spread of Ge–O bond distances ranging from 1.76–1.78 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Ta5+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two K1+, one Ta5+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+, one Ta5+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Ta5+, and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Ta5+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Ta5+, and one Ge4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+ and two Ta5+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Ta5+, and one Ge4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Ta5+ atoms.