Ca3Rh8B6 crystallizes in the orthorhombic Fmmm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 17-coordinate geometry to one Ca(2), two equivalent Rh(2), four equivalent Rh(1), four equivalent Rh(3), and six equivalent B(1) atoms. In the second Ca site, Ca(2) is bonded in a 20-coordinate geometry to two equivalent Ca(1), four equivalent Rh(2), eight equivalent Rh(1), and six equivalent B(2) atoms. There are three inequivalent Rh sites. In the first Rh site, Rh(1) is bonded in a distorted square co-planar geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent B(1), and two equivalent B(2) atoms. In the second Rh site, Rh(2) is bonded in a distorted square co-planar geometry to two equivalent Ca(1); two equivalent Ca(2); two equivalent B(1); and two B(2,2) atoms. In the third Rh site, Rh(3) is bonded in a 4-coordinate geometry to four equivalent Ca(1) and four equivalent B(1) atoms. There are three inequivalent B sites. In the first B site, B(1) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Rh(2), two equivalent Rh(1), and two equivalent Rh(3) atoms. In the second B site, B(2) is bonded in a 6-coordinate geometry to three equivalent Ca(2), two equivalent Rh(2), and four equivalent Rh(1) atoms. In the third B site, B(2) is bonded in a 6-coordinate geometry to three equivalent Ca(2), two equivalent Rh(2), and four equivalent Rh(1) atoms.
Ca3Rh8B6 crystallizes in the orthorhombic Fmmm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 17-coordinate geometry to one Ca(2), two equivalent Rh(2), four equivalent Rh(1), four equivalent Rh(3), and six equivalent B(1) atoms. The Ca(1)-Ca(2) bond length is 3.09 Å. Both Ca(1)-Rh(2) bond lengths are 3.20 Å. All Ca(1)-Rh(1) bond lengths are 3.25 Å. All Ca(1)-Rh(3) bond lengths are 3.03 Å. There are two shorter (2.95 Å) and four longer (3.17 Å) Ca(1)-B(1) bond lengths. In the second Ca site, Ca(2) is bonded in a 20-coordinate geometry to two equivalent Ca(1), four equivalent Rh(2), eight equivalent Rh(1), and six equivalent B(2) atoms. All Ca(2)-Rh(2) bond lengths are 3.12 Å. All Ca(2)-Rh(1) bond lengths are 3.15 Å. There are four shorter (3.20 Å) and two longer (3.24 Å) Ca(2)-B(2) bond lengths. There are three inequivalent Rh sites. In the first Rh site, Rh(1) is bonded in a distorted square co-planar geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent B(1), and two equivalent B(2) atoms. Both Rh(1)-B(1) bond lengths are 2.20 Å. Both Rh(1)-B(2) bond lengths are 2.15 Å. In the second Rh site, Rh(2) is bonded in a distorted square co-planar geometry to two equivalent Ca(1); two equivalent Ca(2); two equivalent B(1); and two B(2,2) atoms. Both Rh(2)-B(1) bond lengths are 2.12 Å. Both Rh(2)-B(2,2) bond lengths are 2.19 Å. In the third Rh site, Rh(3) is bonded in a 4-coordinate geometry to four equivalent Ca(1) and four equivalent B(1) atoms. All Rh(3)-B(1) bond lengths are 2.11 Å. There are three inequivalent B sites. In the first B site, B(1) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Rh(2), two equivalent Rh(1), and two equivalent Rh(3) atoms. In the second B site, B(2) is bonded in a 6-coordinate geometry to three equivalent Ca(2), two equivalent Rh(2), and four equivalent Rh(1) atoms. In the third B site, B(2) is bonded in a 6-coordinate geometry to three equivalent Ca(2), two equivalent Rh(2), and four equivalent Rh(1) atoms. There are two shorter (3.20 Å) and one longer (3.24 Å) B(2)-Ca(2) bond length. All B(2)-Rh(1) bond lengths are 2.15 Å.