Materials Data on Ho5(SiB4)2 by Materials Project
Ho5Si2B8 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 12-coordinate geometry to nine B and three equivalent Si atoms. There are a spread of Ho–B bond distances ranging from 2.62–2.95 Å. There are one shorter (3.04 Å) and two longer (3.11 Å) Ho–Si bond lengths. In the second Ho site, Ho is bonded to two equivalent B and four equivalent Si atoms to form corner-sharing HoSi4B2 octahedra. The corner-sharing octahedral tilt angles are 57°. Both Ho–B bond lengths are 2.71 Å. All Ho–Si bond lengths are 2.89 Å. There are three inequivalent B sites. In the first B site, B is bonded in a 9-coordinate geometry to four equivalent Ho and five B atoms. There are a spread of B–B bond distances ranging from 1.75–1.83 Å. In the second B site, B is bonded in a 3-coordinate geometry to six equivalent Ho and three B atoms. The B–B bond length is 1.83 Å. In the third B site, B is bonded in a 9-coordinate geometry to five Ho and four equivalent B atoms. Si is bonded in a 9-coordinate geometry to eight Ho and one Si atom. The Si–Si bond length is 2.35 Å.