Materials Data on Na2BeF4 by Materials Project

Na2BeF4 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 pentagonal pyramids that share corners with four equivalent NaF6 octahedra, corners with four equivalent NaF6 pentagonal pyramids, corners with four equivalent BeF4 tetrahedra, edges with two equivalent NaF6 octahedra, and an edgeedge with one BeF4 tetrahedra. The corner-sharing octahedra tilt angles range from 63–72°. There are a spread of Na–F bond distances ranging from 2.28–2.41 Å. In the second Na1+ site, Na1+ is bonded to six F1- atoms to form NaF6 octahedra that share corners with four equivalent NaF6 pentagonal pyramids, corners with two equivalent BeF4 tetrahedra, edges with two equivalent NaF6 octahedra, edges with two equivalent NaF6 pentagonal pyramids, and edges with two equivalent BeF4 tetrahedra. There are a spread of Na–F bond distances ranging from 2.28–2.36 Å. Be2+ is bonded to four F1- atoms to form BeF4 tetrahedra that share corners with two equivalent NaF6 octahedra, corners with four equivalent NaF6 pentagonal pyramids, edges with two equivalent NaF6 octahedra, and an edgeedge with one NaF6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 56°. There are a spread of Be–F bond distances ranging from 1.56–1.59 Å. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one Be2+ atom. In the second F1- site, F1- is bonded in a 1-coordinate geometry to three Na1+ and one Be2+ atom. In the third F1- site, F1- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one Be2+ atom.