Materials Data on K8Zr6BeBr20 by Materials Project
K8BeZr6Br20 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. K is bonded in a 4-coordinate geometry to four Br atoms. There are one shorter (3.15 Å) and three longer (3.37 Å) K–Br bond lengths. Be is bonded to six equivalent Zr atoms to form BeZr6 octahedra that share corners with six equivalent BrK4Zr square pyramids. All Be–Zr bond lengths are 2.40 Å. Zr is bonded to one Be and five Br atoms to form a mixture of corner and edge-sharing ZrBeBr5 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.75 Å) and one longer (2.88 Å) Zr–Br bond lengths. There are three inequivalent Br sites. In the first Br site, Br is bonded to four equivalent K and one Zr atom to form distorted BrK4Zr square pyramids that share a cornercorner with one BeZr6 octahedra, corners with four equivalent BrK4 tetrahedra, and edges with four equivalent BrK4Zr square pyramids. The corner-sharing octahedral tilt angles are 0°. In the second Br site, Br is bonded to four equivalent K atoms to form corner-sharing BrK4 tetrahedra. In the third Br site, Br is bonded in a distorted L-shaped geometry to two equivalent Zr atoms.