Rb2(NbBr3)3 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a 6-coordinate geometry to one Br(1), one Br(3), one Br(4), and three equivalent Br(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Br(4), two equivalent Br(3), and two equivalent Br(6) atoms to form distorted corner-sharing NbBr5 square pyramids. In the second Nb site, Nb(2) is bonded to one Br(1), one Br(2), one Br(3), one Br(5), and one Br(6) atom to form distorted corner-sharing NbBr5 square pyramids. There are six inequivalent Br sites. In the first Br site, Br(5) is bonded in a 2-coordinate geometry to two equivalent Nb(2) atoms. In the second Br site, Br(6) is bonded in a 2-coordinate geometry to one Nb(1) and one Nb(2) atom. In the third Br site, Br(1) is bonded in a 2-coordinate geometry to two equivalent Rb(1) and two equivalent Nb(2) atoms. In the fourth Br site, Br(2) is bonded to three equivalent Rb(1) and one Nb(2) atom to form a mixture of corner and edge-sharing BrRb3Nb tetrahedra. In the fifth Br site, Br(3) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Nb(2) atom. In the sixth Br site, Br(4) is bonded in a trigonal planar geometry to two equivalent Rb(1) and one Nb(1) atom.
Rb2(NbBr3)3 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a 6-coordinate geometry to one Br(1), one Br(3), one Br(4), and three equivalent Br(2) atoms. The Rb(1)-Br(1) bond length is 3.86 Å. The Rb(1)-Br(3) bond length is 3.67 Å. The Rb(1)-Br(4) bond length is 3.31 Å. There are a spread of Rb(1)-Br(2) bond distances ranging from 3.37-3.43 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Br(4), two equivalent Br(3), and two equivalent Br(6) atoms to form distorted corner-sharing NbBr5 square pyramids. The Nb(1)-Br(4) bond length is 2.81 Å. Both Nb(1)-Br(3) bond lengths are 2.63 Å. Both Nb(1)-Br(6) bond lengths are 2.62 Å. In the second Nb site, Nb(2) is bonded to one Br(1), one Br(2), one Br(3), one Br(5), and one Br(6) atom to form distorted corner-sharing NbBr5 square pyramids. The Nb(2)-Br(1) bond length is 2.63 Å. The Nb(2)-Br(2) bond length is 2.86 Å. The Nb(2)-Br(3) bond length is 2.63 Å. The Nb(2)-Br(5) bond length is 2.63 Å. The Nb(2)-Br(6) bond length is 2.61 Å. There are six inequivalent Br sites. In the first Br site, Br(5) is bonded in a 2-coordinate geometry to two equivalent Nb(2) atoms. In the second Br site, Br(6) is bonded in a 2-coordinate geometry to one Nb(1) and one Nb(2) atom. In the third Br site, Br(1) is bonded in a 2-coordinate geometry to two equivalent Rb(1) and two equivalent Nb(2) atoms. In the fourth Br site, Br(2) is bonded to three equivalent Rb(1) and one Nb(2) atom to form a mixture of corner and edge-sharing BrRb3Nb tetrahedra. In the fifth Br site, Br(3) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Nb(2) atom. In the sixth Br site, Br(4) is bonded in a trigonal planar geometry to two equivalent Rb(1) and one Nb(1) atom.