Materials Data on KCaNb2O6F by Materials Project

Dataset · Sat May 02 04:00:00 EDT 2020

DOI:https://doi.org/10.17188/1283751· OSTI ID:1283751

KCaNb2O6F crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. K1+ is bonded to six O2- and two equivalent F1- atoms to form distorted KO6F2 hexagonal bipyramids that share edges with two equivalent KO6F2 hexagonal bipyramids, edges with four equivalent CaO6F2 hexagonal bipyramids, and edges with six NbO6 octahedra. There are two shorter (2.78 Å) and four longer (2.80 Å) K–O bond lengths. Both K–F bond lengths are 2.50 Å. Ca2+ is bonded to six O2- and two equivalent F1- atoms to form distorted CaO6F2 hexagonal bipyramids that share edges with two equivalent CaO6F2 hexagonal bipyramids, edges with four equivalent KO6F2 hexagonal bipyramids, and edges with six NbO6 octahedra. There are four shorter (2.69 Å) and two longer (2.73 Å) Ca–O bond lengths. Both Ca–F bond lengths are 2.18 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra, edges with two equivalent CaO6F2 hexagonal bipyramids, and edges with four equivalent KO6F2 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 37–40°. There are two shorter (2.01 Å) and four longer (2.03 Å) Nb–O bond lengths. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra, edges with two equivalent KO6F2 hexagonal bipyramids, and edges with four equivalent CaO6F2 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–43°. There are two shorter (2.01 Å) and four longer (2.02 Å) Nb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, one Ca2+, and two Nb5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+ and two equivalent Nb5+ atoms. F1- is bonded to two equivalent K1+ and two equivalent Ca2+ atoms to form distorted corner-sharing FK2Ca2 tetrahedra.

• Research Organization: LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Contributing Organization: The Materials Project; MIT; UC Berkeley; Duke; U Louvain
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1283751
• Report Number(s): mp-682067
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Ca-F-K-Nb-O
KCaNb2O6F
crystal structure