RbNb4Br11 crystallizes in the orthorhombic Pmma space group. Rb(1) is bonded in a 12-coordinate geometry to two equivalent Br(3), two equivalent Br(4), four equivalent Br(2), and four equivalent Br(5) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one Br(1), one Br(4), two equivalent Br(2), and two equivalent Br(5) atoms. In the second Nb site, Nb(2) is bonded to two equivalent Br(1), two equivalent Br(2), and two equivalent Br(3) atoms to form distorted edge-sharing NbBr6 octahedra. There are five inequivalent Br sites. In the first Br site, Br(1) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Nb(2) atoms. In the second Br site, Br(2) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Nb(2) atom. In the third Br site, Br(3) is bonded in a distorted water-like geometry to one Rb(1) and two equivalent Nb(2) atoms. In the fourth Br site, Br(4) is bonded to two equivalent Rb(1) and two equivalent Nb(1) atoms to form distorted corner-sharing BrRb2Nb2 trigonal pyramids. In the fifth Br site, Br(5) is bonded in a distorted L-shaped geometry to two equivalent Rb(1) and two equivalent Nb(1) atoms.
RbNb4Br11 crystallizes in the orthorhombic Pmma space group. Rb(1) is bonded in a 12-coordinate geometry to two equivalent Br(3), two equivalent Br(4), four equivalent Br(2), and four equivalent Br(5) atoms. Both Rb(1)-Br(3) bond lengths are 3.86 Å. Both Rb(1)-Br(4) bond lengths are 3.72 Å. All Rb(1)-Br(2) bond lengths are 3.66 Å. There are two shorter (4.01 Å) and two longer (4.13 Å) Rb(1)-Br(5) bond lengths. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one Br(1), one Br(4), two equivalent Br(2), and two equivalent Br(5) atoms. The Nb(1)-Br(1) bond length is 2.58 Å. The Nb(1)-Br(4) bond length is 2.82 Å. Both Nb(1)-Br(2) bond lengths are 2.57 Å. Both Nb(1)-Br(5) bond lengths are 2.74 Å. In the second Nb site, Nb(2) is bonded to two equivalent Br(1), two equivalent Br(2), and two equivalent Br(3) atoms to form distorted edge-sharing NbBr6 octahedra. Both Nb(2)-Br(1) bond lengths are 2.64 Å. Both Nb(2)-Br(2) bond lengths are 2.66 Å. Both Nb(2)-Br(3) bond lengths are 2.77 Å. There are five inequivalent Br sites. In the first Br site, Br(1) is bonded in a 3-coordinate geometry to one Nb(1) and two equivalent Nb(2) atoms. In the second Br site, Br(2) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Nb(2) atom. In the third Br site, Br(3) is bonded in a distorted water-like geometry to one Rb(1) and two equivalent Nb(2) atoms. In the fourth Br site, Br(4) is bonded to two equivalent Rb(1) and two equivalent Nb(1) atoms to form distorted corner-sharing BrRb2Nb2 trigonal pyramids. In the fifth Br site, Br(5) is bonded in a distorted L-shaped geometry to two equivalent Rb(1) and two equivalent Nb(1) atoms.