Materials Data on ErB4 by Materials Project
ErB4 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Er is bonded in a 4-coordinate geometry to eighteen B atoms. There are a spread of Er–B bond distances ranging from 2.71–3.06 Å. There are three inequivalent B sites. In the first B site, B is bonded in a 1-coordinate geometry to four equivalent Er and five B atoms. There is one shorter (1.62 Å) and four longer (1.74 Å) B–B bond length. In the second B site, B is bonded in a 9-coordinate geometry to four equivalent Er and five B atoms. There is one shorter (1.71 Å) and two longer (1.81 Å) B–B bond length. In the third B site, B is bonded in a distorted trigonal planar geometry to six equivalent Er and three B atoms. The B–B bond length is 1.74 Å.