RbNb3CuCl9 crystallizes in the triclinic P-1 space group. Rb(1) is bonded to one Cl(2), one Cl(4), one Cl(5), one Cl(6), one Cl(8), one Cl(9), two equivalent Cl(1), two equivalent Cl(3), and two equivalent Cl(7) atoms to form RbCl12 cuboctahedra that share corners with two equivalent Nb(2)Cl5 square pyramids, corners with three equivalent Nb(1)Cl5 square pyramids, corners with three equivalent Nb(3)Cl5 square pyramids, corners with three equivalent Cu(1)Cl4 tetrahedra,  an edgeedge with one Rb(1)Cl12 cuboctahedra,  an edgeedge with one Cu(1)Cl4 tetrahedra,  a faceface with one Rb(1)Cl12 cuboctahedra,  a faceface with one Nb(1)Cl5 square pyramid,  a faceface with one Nb(3)Cl5 square pyramid, and faces with two equivalent Nb(2)Cl5 square pyramids. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Cl(4), one Cl(5), one Cl(6), one Cl(7), and one Cl(9) atom to form distorted NbCl5 square pyramids that share corners with three equivalent Rb(1)Cl12 cuboctahedra, corners with two equivalent Nb(2)Cl5 square pyramids, corners with two equivalent Nb(3)Cl5 square pyramids,  a cornercorner with one Cu(1)Cl4 tetrahedra, and  a faceface with one Rb(1)Cl12 cuboctahedra. In the second Nb site, Nb(2) is bonded to one Cl(1), one Cl(3), one Cl(6), one Cl(7), and one Cl(8) atom to form distorted NbCl5 square pyramids that share corners with two equivalent Rb(1)Cl12 cuboctahedra, corners with two equivalent Nb(1)Cl5 square pyramids, corners with two equivalent Nb(3)Cl5 square pyramids,  a cornercorner with one Cu(1)Cl4 tetrahedra, and faces with two equivalent Rb(1)Cl12 cuboctahedra. In the third Nb site, Nb(3) is bonded to one Cl(2), one Cl(3), one Cl(5), one Cl(8), and one Cl(9) atom to form distorted NbCl5 square pyramids that share corners with three equivalent Rb(1)Cl12 cuboctahedra, corners with two equivalent Nb(1)Cl5 square pyramids, corners with two equivalent Nb(2)Cl5 square pyramids, corners with two equivalent Cu(1)Cl4 tetrahedra, and  a faceface with one Rb(1)Cl12 cuboctahedra. Cu(1) is bonded to one Cl(1), one Cl(4), and two equivalent Cl(2) atoms to form distorted CuCl4 tetrahedra that share corners with three equivalent Rb(1)Cl12 cuboctahedra,  a cornercorner with one Nb(1)Cl5 square pyramid,  a cornercorner with one Nb(2)Cl5 square pyramid, corners with two equivalent Nb(3)Cl5 square pyramids,  an edgeedge with one Rb(1)Cl12 cuboctahedra, and  an edgeedge with one Cu(1)Cl4 tetrahedra. There are nine inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 4-coordinate geometry to two equivalent Rb(1), one Nb(2), and one Cu(1) atom. In the second Cl site, Cl(2) is bonded in a 4-coordinate geometry to one Rb(1), one Nb(3), and two equivalent Cu(1) atoms. In the third Cl site, Cl(3) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Nb(2), and one Nb(3) atom. In the fourth Cl site, Cl(4) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Cu(1) atom. In the fifth Cl site, Cl(5) is bonded in a 2-coordinate geometry to one Rb(1), one Nb(1), and one Nb(3) atom. In the sixth Cl site, Cl(6) is bonded in a 2-coordinate geometry to one Rb(1), one Nb(1), and one Nb(2) atom. In the seventh Cl site, Cl(7) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Nb(1), and one Nb(2) atom. In the eighth Cl site, Cl(8) is bonded in a 2-coordinate geometry to one Rb(1), one Nb(2), and one Nb(3) atom. In the ninth Cl site, Cl(9) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Nb(3) atom.
RbNb3CuCl9 crystallizes in the triclinic P-1 space group. Rb(1) is bonded to one Cl(2), one Cl(4), one Cl(5), one Cl(6), one Cl(8), one Cl(9), two equivalent Cl(1), two equivalent Cl(3), and two equivalent Cl(7) atoms to form RbCl12 cuboctahedra that share corners with two equivalent Nb(2)Cl5 square pyramids, corners with three equivalent Nb(1)Cl5 square pyramids, corners with three equivalent Nb(3)Cl5 square pyramids, corners with three equivalent Cu(1)Cl4 tetrahedra,  an edgeedge with one Rb(1)Cl12 cuboctahedra,  an edgeedge with one Cu(1)Cl4 tetrahedra,  a faceface with one Rb(1)Cl12 cuboctahedra,  a faceface with one Nb(1)Cl5 square pyramid,  a faceface with one Nb(3)Cl5 square pyramid, and faces with two equivalent Nb(2)Cl5 square pyramids. The Rb(1)-Cl(2) bond length is 3.61 Å. The Rb(1)-Cl(4) bond length is 3.48 Å. The Rb(1)-Cl(5) bond length is 3.63 Å. The Rb(1)-Cl(6) bond length is 3.66 Å. The Rb(1)-Cl(8) bond length is 3.69 Å. The Rb(1)-Cl(9) bond length is 3.55 Å. There is one shorter (3.41 Å) and one longer (3.59 Å) Rb(1)-Cl(1) bond length. There is one shorter (3.63 Å) and one longer (3.66 Å) Rb(1)-Cl(3) bond length. There is one shorter (3.65 Å) and one longer (3.68 Å) Rb(1)-Cl(7) bond length. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one Cl(4), one Cl(5), one Cl(6), one Cl(7), and one Cl(9) atom to form distorted NbCl5 square pyramids that share corners with three equivalent Rb(1)Cl12 cuboctahedra, corners with two equivalent Nb(2)Cl5 square pyramids, corners with two equivalent Nb(3)Cl5 square pyramids,  a cornercorner with one Cu(1)Cl4 tetrahedra, and  a faceface with one Rb(1)Cl12 cuboctahedra. The Nb(1)-Cl(4) bond length is 2.64 Å. The Nb(1)-Cl(5) bond length is 2.47 Å. The Nb(1)-Cl(6) bond length is 2.47 Å. The Nb(1)-Cl(7) bond length is 2.49 Å. The Nb(1)-Cl(9) bond length is 2.48 Å. In the second Nb site, Nb(2) is bonded to one Cl(1), one Cl(3), one Cl(6), one Cl(7), and one Cl(8) atom to form distorted NbCl5 square pyramids that share corners with two equivalent Rb(1)Cl12 cuboctahedra, corners with two equivalent Nb(1)Cl5 square pyramids, corners with two equivalent Nb(3)Cl5 square pyramids,  a cornercorner with one Cu(1)Cl4 tetrahedra, and faces with two equivalent Rb(1)Cl12 cuboctahedra. The Nb(2)-Cl(1) bond length is 2.69 Å. The Nb(2)-Cl(3) bond length is 2.49 Å. The Nb(2)-Cl(6) bond length is 2.47 Å. The Nb(2)-Cl(7) bond length is 2.49 Å. The Nb(2)-Cl(8) bond length is 2.48 Å. In the third Nb site, Nb(3) is bonded to one Cl(2), one Cl(3), one Cl(5), one Cl(8), and one Cl(9) atom to form distorted NbCl5 square pyramids that share corners with three equivalent Rb(1)Cl12 cuboctahedra, corners with two equivalent Nb(1)Cl5 square pyramids, corners with two equivalent Nb(2)Cl5 square pyramids, corners with two equivalent Cu(1)Cl4 tetrahedra, and  a faceface with one Rb(1)Cl12 cuboctahedra. The Nb(3)-Cl(2) bond length is 2.71 Å. The Nb(3)-Cl(3) bond length is 2.48 Å. The Nb(3)-Cl(5) bond length is 2.46 Å. The Nb(3)-Cl(8) bond length is 2.47 Å. The Nb(3)-Cl(9) bond length is 2.48 Å. Cu(1) is bonded to one Cl(1), one Cl(4), and two equivalent Cl(2) atoms to form distorted CuCl4 tetrahedra that share corners with three equivalent Rb(1)Cl12 cuboctahedra,  a cornercorner with one Nb(1)Cl5 square pyramid,  a cornercorner with one Nb(2)Cl5 square pyramid, corners with two equivalent Nb(3)Cl5 square pyramids,  an edgeedge with one Rb(1)Cl12 cuboctahedra, and  an edgeedge with one Cu(1)Cl4 tetrahedra. The Cu(1)-Cl(1) bond length is 2.32 Å. The Cu(1)-Cl(4) bond length is 2.28 Å. There is one shorter (2.33 Å) and one longer (2.64 Å) Cu(1)-Cl(2) bond length. There are nine inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a 4-coordinate geometry to two equivalent Rb(1), one Nb(2), and one Cu(1) atom. In the second Cl site, Cl(2) is bonded in a 4-coordinate geometry to one Rb(1), one Nb(3), and two equivalent Cu(1) atoms. In the third Cl site, Cl(3) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Nb(2), and one Nb(3) atom. In the fourth Cl site, Cl(4) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Cu(1) atom. In the fifth Cl site, Cl(5) is bonded in a 2-coordinate geometry to one Rb(1), one Nb(1), and one Nb(3) atom. In the sixth Cl site, Cl(6) is bonded in a 2-coordinate geometry to one Rb(1), one Nb(1), and one Nb(2) atom. In the seventh Cl site, Cl(7) is bonded in a 2-coordinate geometry to two equivalent Rb(1), one Nb(1), and one Nb(2) atom. In the eighth Cl site, Cl(8) is bonded in a 2-coordinate geometry to one Rb(1), one Nb(2), and one Nb(3) atom. In the ninth Cl site, Cl(9) is bonded in a 3-coordinate geometry to one Rb(1), one Nb(1), and one Nb(3) atom.