Title: Materials Data on K2NaNb(OF2)2 by Materials Project

Abstract

K2NaNbO2F4 is (Cubic) Perovskite-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to four O2- and eight F1- atoms to form KO4F8 cuboctahedra that share corners with twelve KO4F8 cuboctahedra, faces with six KO4F8 cuboctahedra, faces with four NaO2F4 octahedra, and faces with four NbO2F4 octahedra. There are a spread of K–O bond distances ranging from 3.02–3.09 Å. There are a spread of K–F bond distances ranging from 3.01–3.08 Å. In the second K1+ site, K1+ is bonded to four O2- and eight F1- atoms to form KO4F8 cuboctahedra that share corners with twelve KO4F8 cuboctahedra, faces with six KO4F8 cuboctahedra, faces with four NaO2F4 octahedra, and faces with four NbO2F4 octahedra. There are a spread of K–O bond distances ranging from 3.02–3.07 Å. There are a spread of K–F bond distances ranging from 2.99–3.10 Å. In the third K1+ site, K1+ is bonded to four O2- and eight F1- atoms to form KO4F8 cuboctahedra that share corners with twelve KO4F8 cuboctahedra, faces with six KO4F8 cuboctahedra, faces with four NaO2F4 octahedra, and faces with four NbO2F4 octahedra. There are amore » spread of K–O bond distances ranging from 3.01–3.11 Å. There are a spread of K–F bond distances ranging from 3.03–3.11 Å. In the fourth K1+ site, K1+ is bonded to four O2- and eight F1- atoms to form KO4F8 cuboctahedra that share corners with twelve KO4F8 cuboctahedra, faces with six KO4F8 cuboctahedra, faces with four NaO2F4 octahedra, and faces with four NbO2F4 octahedra. There are a spread of K–O bond distances ranging from 3.03–3.13 Å. There are a spread of K–F bond distances ranging from 3.00–3.10 Å. There are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to two O2- and four F1- atoms to form NaO2F4 octahedra that share corners with six NbO2F4 octahedra and faces with eight KO4F8 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are one shorter (2.39 Å) and one longer (2.40 Å) Na–O bond lengths. There are a spread of Na–F bond distances ranging from 2.26–2.30 Å. In the second Na1+ site, Na1+ is bonded to two O2- and four F1- atoms to form NaO2F4 octahedra that share corners with six NbO2F4 octahedra and faces with eight KO4F8 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are one shorter (2.38 Å) and one longer (2.41 Å) Na–O bond lengths. There are a spread of Na–F bond distances ranging from 2.25–2.29 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to two O2- and four F1- atoms to form NbO2F4 octahedra that share corners with six NaO2F4 octahedra and faces with eight KO4F8 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There is one shorter (1.90 Å) and one longer (1.91 Å) Nb–O bond length. There are two shorter (2.03 Å) and two longer (2.04 Å) Nb–F bond lengths. In the second Nb5+ site, Nb5+ is bonded to two O2- and four F1- atoms to form NbO2F4 octahedra that share corners with six NaO2F4 octahedra and faces with eight KO4F8 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There is one shorter (1.90 Å) and one longer (1.91 Å) Nb–O bond length. There are one shorter (2.03 Å) and three longer (2.04 Å) Nb–F bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four K1+, one Na1+, and one Nb5+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to four K1+, one Na1+, and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the second F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the third F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the fourth F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the fifth F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the sixth F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the seventh F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom. In the eighth F1- site, F1- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Nb5+ atom.« less

Authors:

The Materials Project

Publication Date:

Wed Mar 27 00:00:00 EDT 2019

Other Number(s):

mp-684816

DOE Contract Number:  

AC02-05CH11231; EDCBEE

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). LBNL Materials Project

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

Collaborations:

MIT; UC Berkeley; Duke; U Louvain

Subject:

36 MATERIALS SCIENCE

Keywords:

crystal structure; K2NaNb(OF2)2; F-K-Na-Nb-O

OSTI Identifier:

1284010

DOI:

https://doi.org/10.17188/1284010