DOE OSTI2020
RhC3As3H9(OBr)3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two RhC3As3H9(OBr)3 clusters. Rh3+ is bonded to three As3- and three Br1- atoms to form RhAs3Br3 octahedra that share corners with three CAsH3 tetrahedra. All Rh–As bond lengths are 2.39 Å. There are one shorter (2.55 Å) and two longer (2.56 Å) Rh–Br bond lengths. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded to one As3- and three H1+ atoms to form distorted CAsH3 tetrahedra that share a cornercorner with one RhAs3Br3 octahedra. The corner-sharing octahedral tilt angles are 55°. The C–As bond length is 1.94 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. In the second C2+ site, C2+ is bonded to one As3- and three H1+ atoms to form distorted CAsH3 tetrahedra that share a cornercorner with one RhAs3Br3 octahedra. The corner-sharing octahedral tilt angles are 56°. The C–As bond length is 1.94 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. In the third C2+ site, C2+ is bonded to one As3- and three H1+ atoms to form distorted CAsH3 tetrahedra that share a cornercorner with one RhAs3Br3 octahedra. The corner-sharing octahedral tilt angles are 56°. The C–As bond length is 1.95 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 4-coordinate geometry to one Rh3+, one C2+, and two O2- atoms. Both As–O bond lengths are 1.82 Å. In the second As3- site, As3- is bonded in a 4-coordinate geometry to one Rh3+, one C2+, and two O2- atoms. There is one shorter (1.81 Å) and one longer (1.82 Å) As–O bond length. In the third As3- site, As3- is bonded in a 4-coordinate geometry to one Rh3+, one C2+, and two O2- atoms. Both As–O bond lengths are 1.82 Å. There are nine inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two As3- atoms. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two As3- atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two As3- atoms. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Rh3+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Rh3+ atom. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Rh3+ atom.