Materials Data on KYTa2O7 by Materials Project
KYTa2O7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. K1+ is bonded to eight O2- atoms to form KO8 hexagonal bipyramids that share edges with two equivalent KO8 hexagonal bipyramids, edges with four equivalent YO8 hexagonal bipyramids, and edges with six TaO6 octahedra. There are two shorter (2.53 Å) and six longer (2.78 Å) K–O bond lengths. Y3+ is bonded to eight O2- atoms to form distorted YO8 hexagonal bipyramids that share edges with two equivalent YO8 hexagonal bipyramids, edges with four equivalent KO8 hexagonal bipyramids, and edges with six TaO6 octahedra. There are a spread of Y–O bond distances ranging from 2.12–2.73 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra, edges with two equivalent KO8 hexagonal bipyramids, and edges with four equivalent YO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 41–42°. There are two shorter (1.99 Å) and four longer (2.01 Å) Ta–O bond lengths. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra, edges with two equivalent YO8 hexagonal bipyramids, and edges with four equivalent KO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 36–41°. There are two shorter (1.99 Å) and four longer (2.02 Å) Ta–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent K1+ and two equivalent Y3+ atoms to form distorted corner-sharing OK2Y2 tetrahedra. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Y3+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, one Y3+, and two Ta5+ atoms.