Materials Data on K4Nb6O17 by Materials Project
K4Nb6O17 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.77–3.41 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 2.92–3.25 Å. In the third K1+ site, K1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 2.67–2.73 Å. In the fourth K1+ site, K1+ is bonded in a 3-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.70–3.24 Å. There are six inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.85–2.38 Å. In the second Nb5+ site, Nb5+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.80–2.52 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 2–19°. There are a spread of Nb–O bond distances ranging from 1.88–2.22 Å. In the fourth Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.81–2.36 Å. In the fifth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 14–19°. There are a spread of Nb–O bond distances ranging from 1.88–2.23 Å. In the sixth Nb5+ site, Nb5+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Nb–O bond distances ranging from 1.81–2.36 Å. There are seventeen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two K1+ and one Nb5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two K1+ and two Nb5+ atoms. In the third O2- site, O2- is bonded to one K1+ and three Nb5+ atoms to form distorted corner-sharing OKNb3 trigonal pyramids. In the fourth O2- site, O2- is bonded in a distorted linear geometry to three K1+ and two Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two K1+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two K1+ and two Nb5+ atoms. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to four K1+ and one Nb5+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to two K1+ and two Nb5+ atoms. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to two Nb5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Nb5+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted linear geometry to three K1+ and two Nb5+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to four K1+ and one Nb5+ atom. In the sixteenth O2- site, O2- is bonded to one K1+ and three Nb5+ atoms to form distorted corner-sharing OKNb3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one K1+ and two Nb5+ atoms.