Materials Data on AlNi9B8 by Materials Project

Ni9B8Al crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional and consists of four aluminum molecules and one Ni9B8 framework. In the Ni9B8 framework, there are four inequivalent Ni+1.67+ sites. In the first Ni+1.67+ site, Ni+1.67+ is bonded to six B+2.25- atoms to form distorted edge-sharing NiB6 octahedra. There are four shorter (2.12 Å) and two longer (2.20 Å) Ni–B bond lengths. In the second Ni+1.67+ site, Ni+1.67+ is bonded in a 6-coordinate geometry to six B+2.25- atoms. There are a spread of Ni–B bond distances ranging from 2.10–2.28 Å. In the third Ni+1.67+ site, Ni+1.67+ is bonded to six B+2.25- atoms to form a mixture of distorted corner, edge, and face-sharing NiB6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Ni–B bond distances ranging from 2.14–2.16 Å. In the fourth Ni+1.67+ site, Ni+1.67+ is bonded in a 6-coordinate geometry to six B+2.25- atoms. There are a spread of Ni–B bond distances ranging from 2.08–2.29 Å. There are four inequivalent B+2.25- sites. In the first B+2.25- site, B+2.25- is bonded in a 9-coordinate geometry to eight Ni+1.67+ and one B+2.25- atom. The B–B bond length is 1.74 Å. In the second B+2.25- site, B+2.25- is bonded in a 9-coordinate geometry to six Ni+1.67+ and three B+2.25- atoms. Both B–B bond lengths are 1.77 Å. In the third B+2.25- site, B+2.25- is bonded in a 9-coordinate geometry to six Ni+1.67+ and three B+2.25- atoms. Both B–B bond lengths are 1.73 Å. In the fourth B+2.25- site, B+2.25- is bonded in a 9-coordinate geometry to seven Ni+1.67+ and two B+2.25- atoms. The B–B bond length is 1.78 Å.