Materials Data on K2ErF5 by Materials Project
K2ErF5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of K–F bond distances ranging from 2.67–2.92 Å. Er3+ is bonded to seven F1- atoms to form distorted edge-sharing ErF7 pentagonal bipyramids. There are a spread of Er–F bond distances ranging from 2.18–2.28 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to four equivalent K1+ and one Er3+ atom. In the second F1- site, F1- is bonded in a 5-coordinate geometry to four equivalent K1+ and one Er3+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent K1+ and two equivalent Er3+ atoms. In the fourth F1- site, F1- is bonded in a 5-coordinate geometry to four equivalent K1+ and one Er3+ atom.