Materials Data on Ca2(Ni7B2)3 by Materials Project
Ca2(Ni7B2)3 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca is bonded to sixteen Ni atoms to form distorted CaNi16 tetrahedra that share edges with six equivalent CaNi16 tetrahedra and faces with four equivalent NiNi12 cuboctahedra. There are four shorter (2.55 Å) and twelve longer (2.95 Å) Ca–Ni bond lengths. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a distorted bent 150 degrees geometry to two equivalent Ca, one Ni, and two equivalent B atoms. The Ni–Ni bond length is 2.53 Å. Both Ni–B bond lengths are 2.11 Å. In the second Ni site, Ni is bonded to one Ca and three equivalent B atoms to form a mixture of corner and edge-sharing NiCaB3 tetrahedra. All Ni–B bond lengths are 2.10 Å. In the third Ni site, Ni is bonded to twelve equivalent Ni atoms to form NiNi12 cuboctahedra that share faces with eight equivalent CaNi16 tetrahedra. B is bonded in a 8-coordinate geometry to eight Ni atoms.