Materials Data on KYbBeF6 by Materials Project
KBeYbF6 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. K1+ is bonded to twelve F1- atoms to form KF12 cuboctahedra that share corners with two equivalent KF12 cuboctahedra, corners with two equivalent BeF4 tetrahedra, edges with two equivalent KF12 cuboctahedra, edges with three equivalent BeF4 tetrahedra, and faces with two equivalent KF12 cuboctahedra. There are a spread of K–F bond distances ranging from 2.90–3.23 Å. Be2+ is bonded to four F1- atoms to form BeF4 tetrahedra that share corners with two equivalent KF12 cuboctahedra and edges with three equivalent KF12 cuboctahedra. There are a spread of Be–F bond distances ranging from 1.53–1.61 Å. Yb3+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Yb–F bond distances ranging from 2.20–2.36 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to two equivalent K1+, one Be2+, and one Yb3+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one K1+, one Be2+, and one Yb3+ atom. In the third F1- site, F1- is bonded in a 2-coordinate geometry to two equivalent K1+, two equivalent Yb3+, and one F1- atom. The F–F bond length is 1.99 Å. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to three equivalent K1+, one Be2+, and one Yb3+ atom.