Materials Data on KEuF4 by Materials Project
KEuF4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven F1- atoms. There are a spread of K–F bond distances ranging from 2.62–2.76 Å. Eu3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Eu–F bond distances ranging from 2.31–2.51 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded to two equivalent K1+ and two equivalent Eu3+ atoms to form distorted FK2Eu2 tetrahedra that share corners with ten FK2Eu2 tetrahedra and an edgeedge with one FKEu3 tetrahedra. In the second F1- site, F1- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Eu3+ atoms. In the third F1- site, F1- is bonded to one K1+ and three equivalent Eu3+ atoms to form FKEu3 tetrahedra that share corners with eight FK2Eu2 tetrahedra and edges with three FKEu3 tetrahedra. In the fourth F1- site, F1- is bonded in a 5-coordinate geometry to four equivalent K1+ and one Eu3+ atom.