Materials Data on Na2MgScF7 by Materials Project

Abstract

Na2MgScF7 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Na–F bond distances ranging from 2.26–2.98 Å. In the second Na1+ site, Na1+ is bonded in a distorted body-centered cubic geometry to eight F1- atoms. There are four shorter (2.46 Å) and four longer (2.81 Å) Na–F bond lengths. Mg2+ is bonded to six F1- atoms to form MgF6 octahedra that share corners with two equivalent MgF6 octahedra and corners with four equivalent ScF6 octahedra. The corner-sharing octahedra tilt angles range from 36–44°. There is two shorter (1.94 Å) and four longer (2.01 Å) Mg–F bond length. Sc3+ is bonded to six F1- atoms to form ScF6 octahedra that share corners with four equivalent MgF6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are four shorter (2.03 Å) and two longer (2.06 Å) Sc–F bond lengths. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded to three Na1+ and one Sc3+ atom to form a mixture of distorted edge and corner-sharing FNa3Sc tetrahedra. In the second F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one Mg2+, and one Sc3+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to two Na1+, one Mg2+, and one Sc3+ atom. In the fourth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Na1+ and two equivalent Mg2+ atoms. In the fifth F1- site, F1- is bonded to three Na1+ and one Sc3+ atom to form a mixture of distorted edge and corner-sharing FNa3Sc tetrahedra. In the sixth F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent Na1+ and two equivalent Mg2+ atoms.