Materials Data on K5Nb4O12F by Materials Project

Abstract

K5(NbO3)4F is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to five O2- and one F1- atom. There are a spread of K–O bond distances ranging from 2.67–3.07 Å. The K–F bond length is 2.74 Å. In the second K1+ site, K1+ is bonded to four O2- and two equivalent F1- atoms to form corner-sharing KO4F2 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.67 Å) and two longer (2.72 Å) K–O bond lengths. Both K–F bond lengths are 2.59 Å. In the third K1+ site, K1+ is bonded in a 5-coordinate geometry to six O2- and one F1- atom. There are a spread of K–O bond distances ranging from 2.68–3.34 Å. The K–F bond length is 2.73 Å. There are two 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 1.81–2.49 Å. In the second 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 1.81–2.46 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two K1+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to four K1+ and one Nb5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two K1+ and two Nb5+ atoms. F1- is bonded to six K1+ atoms to form corner-sharing FK6 octahedra. The corner-sharing octahedral tilt angles are 0°.