DOE OSTI2020
Ca3Rh8B6 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. there are three inequivalent Ca sites. In the first Ca site, Ca is bonded in a 6-coordinate geometry to one Ca, ten Rh, and six equivalent B atoms. The Ca–Ca bond length is 3.12 Å. There are a spread of Ca–Rh bond distances ranging from 3.05–3.28 Å. There are two shorter (2.97 Å) and four longer (3.20 Å) Ca–B bond lengths. In the second Ca site, Ca is bonded in a 12-coordinate geometry to two equivalent Ca, twelve Rh, and six B atoms. There are four shorter (3.15 Å) and eight longer (3.17 Å) Ca–Rh bond lengths. There are four shorter (3.22 Å) and two longer (3.27 Å) Ca–B bond lengths. In the third Ca site, Ca is bonded in a 6-coordinate geometry to one Ca, ten Rh, and six equivalent B atoms. The Ca–Ca bond length is 3.12 Å. There are a spread of Ca–Rh bond distances ranging from 3.05–3.28 Å. There are two shorter (2.97 Å) and four longer (3.20 Å) Ca–B bond lengths. There are three inequivalent Rh sites. In the first Rh site, Rh is bonded in a distorted square co-planar geometry to four Ca and four B atoms. There are two shorter (2.17 Å) and two longer (2.21 Å) Rh–B bond lengths. In the second Rh site, Rh is bonded in a distorted square co-planar geometry to four Ca and four B atoms. There are two shorter (2.14 Å) and two longer (2.21 Å) Rh–B bond lengths. In the third Rh site, Rh is bonded in a 4-coordinate geometry to four equivalent Ca and four equivalent B atoms. All Rh–B bond lengths are 2.13 Å. There are four inequivalent B sites. In the first B site, B is bonded in a 5-coordinate geometry to three equivalent Ca and five Rh atoms. In the second B site, B is bonded in a 6-coordinate geometry to three equivalent Ca and six Rh atoms. There are two shorter (3.22 Å) and one longer (3.27 Å) B–Ca bond lengths. All B–Rh bond lengths are 2.17 Å. In the third B site, B is bonded in a 6-coordinate geometry to three equivalent Ca and six Rh atoms. Both B–Rh bond lengths are 2.21 Å. In the fourth B site, B is bonded in a 6-coordinate geometry to three equivalent Ca and six Rh atoms. Both B–Rh bond lengths are 2.21 Å.