Materials Data on CaNb4O14 by Materials Project
CaNb4O14 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ca is bonded to eight O atoms to form CaO8 hexagonal bipyramids that share edges with six equivalent NbO6 octahedra. There are two shorter (2.48 Å) and six longer (2.63 Å) Ca–O bond lengths. There are two inequivalent Nb sites. In the first Nb site, Nb is bonded to six equivalent O atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 37°. All Nb–O bond lengths are 2.00 Å. In the second Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and edges with two equivalent CaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 37–42°. There are two shorter (2.00 Å) and four longer (2.01 Å) Nb–O bond lengths. There are three inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Ca atom. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to one Ca and two equivalent Nb atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Nb atoms.