Materials Data on K2Ge2O5 by Materials Project
K2Ge2O5 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are six inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.70–3.32 Å. In the second K1+ site, K1+ is bonded to six O2- atoms to form KO6 octahedra that share corners with six GeO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.62–2.83 Å. In the third 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 2.76–3.10 Å. In the fourth 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 2.70–3.21 Å. In the fifth K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.71–2.97 Å. In the sixth 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 2.63–3.22 Å. There are six inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one KO6 octahedra and corners with three GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 3°. There is one shorter (1.70 Å) and three longer (1.82 Å) Ge–O bond length. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one KO6 octahedra and corners with three GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Ge–O bond distances ranging from 1.69–1.82 Å. In the third Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one KO6 octahedra and corners with three GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Ge–O bond distances ranging from 1.69–1.83 Å. In the fourth Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one KO6 octahedra and corners with three GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 23°. There are a spread of Ge–O bond distances ranging from 1.71–1.83 Å. In the fifth Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one KO6 octahedra and corners with three GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ge–O bond distances ranging from 1.70–1.82 Å. In the sixth Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one KO6 octahedra and corners with three GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of Ge–O bond distances ranging from 1.70–1.83 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two K1+ and two Ge4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two Ge4+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four K1+ and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two K1+ and two Ge4+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to four K1+ and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to four K1+ and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two K1+ and two Ge4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Ge4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Ge4+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Ge4+ atoms. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Ge4+ atoms. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to four K1+ and one Ge4+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to four K1+ and one Ge4+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three K1+ and two Ge4+ atoms. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to three K1+ and one Ge4+ atom.