Materials Data on Na2ScCuF7 by Materials Project
Na2ScCuF7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six F1- atoms to form distorted NaF6 octahedra that share corners with two equivalent NaF7 hexagonal pyramids, corners with two equivalent ScF6 octahedra, corners with two equivalent CuF6 octahedra, edges with two equivalent NaF7 hexagonal pyramids, edges with two equivalent NaF6 octahedra, and edges with two equivalent ScF6 octahedra. The corner-sharing octahedra tilt angles range from 61–68°. There are a spread of Na–F bond distances ranging from 2.40–2.62 Å. In the second Na1+ site, Na1+ is bonded to seven F1- atoms to form NaF7 hexagonal pyramids that share corners with two equivalent NaF6 octahedra, corners with two equivalent ScF6 octahedra, corners with two equivalent CuF6 octahedra, edges with two equivalent NaF6 octahedra, edges with two equivalent ScF6 octahedra, and edges with two equivalent CuF6 octahedra. The corner-sharing octahedra tilt angles range from 52–71°. There are a spread of Na–F bond distances ranging from 2.29–2.57 Å. Sc3+ is bonded to six F1- atoms to form ScF6 octahedra that share corners with two equivalent NaF7 hexagonal pyramids, corners with two equivalent NaF6 octahedra, corners with four equivalent CuF6 octahedra, edges with two equivalent NaF7 hexagonal pyramids, and edges with two equivalent NaF6 octahedra. The corner-sharing octahedra tilt angles range from 35–61°. There are a spread of Sc–F bond distances ranging from 2.02–2.08 Å. Cu2+ is bonded to six F1- atoms to form CuF6 octahedra that share corners with two equivalent NaF7 hexagonal pyramids, corners with two equivalent NaF6 octahedra, corners with two equivalent CuF6 octahedra, corners with four equivalent ScF6 octahedra, and edges with two equivalent NaF7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 35–68°. There are a spread of Cu–F bond distances ranging from 1.93–2.25 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Cu2+ atoms. In the second F1- site, F1- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one Sc3+ atom. In the third F1- site, F1- is bonded to three Na1+ and one Sc3+ atom to form FNa3Sc tetrahedra that share corners with six FNa3Sc tetrahedra and edges with two equivalent FNa2ScCu tetrahedra. In the fourth F1- site, F1- is bonded to two Na1+, one Sc3+, and one Cu2+ atom to form a mixture of distorted edge and corner-sharing FNa2ScCu tetrahedra. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+, one Sc3+, and one Cu2+ atom.