SrCu9Sn4 crystallizes in the tetragonal I4/mcm space group. Sr(1) is bonded in a 24-coordinate geometry to eight equivalent Cu(1), eight equivalent Cu(2), and eight equivalent Sn(1) atoms. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Sr(1), one Cu(3), two equivalent Cu(2), three equivalent Cu(1), and four equivalent Sn(1) atoms to form distorted CuSr2Cu6Sn4 cuboctahedra that share  a cornercorner with one Cu(3)Cu8Sn4 cuboctahedra, corners with seven equivalent Cu(1)Sr2Cu6Sn4 cuboctahedra, edges with four equivalent Cu(1)Sr2Cu6Sn4 cuboctahedra, faces with two equivalent Cu(3)Cu8Sn4 cuboctahedra, and faces with five equivalent Cu(1)Sr2Cu6Sn4 cuboctahedra. In the second Cu site, Cu(2) is bonded in a 12-coordinate geometry to two equivalent Sr(1), one Cu(3), two equivalent Cu(1), three equivalent Cu(2), and four equivalent Sn(1) atoms. In the third Cu site, Cu(3) is bonded to four equivalent Cu(1), four equivalent Cu(2), and four equivalent Sn(1) atoms to form a mixture of face and corner-sharing CuCu8Sn4 cuboctahedra. Sn(1) is bonded in a 11-coordinate geometry to two equivalent Sr(1), one Cu(3), four equivalent Cu(1), and four equivalent Cu(2) atoms.
SrCu9Sn4 crystallizes in the tetragonal I4/mcm space group. Sr(1) is bonded in a 24-coordinate geometry to eight equivalent Cu(1), eight equivalent Cu(2), and eight equivalent Sn(1) atoms. All Sr(1)-Cu(1) bond lengths are 3.66 Å. All Sr(1)-Cu(2) bond lengths are 3.64 Å. All Sr(1)-Sn(1) bond lengths are 3.55 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Sr(1), one Cu(3), two equivalent Cu(2), three equivalent Cu(1), and four equivalent Sn(1) atoms to form distorted CuSr2Cu6Sn4 cuboctahedra that share  a cornercorner with one Cu(3)Cu8Sn4 cuboctahedra, corners with seven equivalent Cu(1)Sr2Cu6Sn4 cuboctahedra, edges with four equivalent Cu(1)Sr2Cu6Sn4 cuboctahedra, faces with two equivalent Cu(3)Cu8Sn4 cuboctahedra, and faces with five equivalent Cu(1)Sr2Cu6Sn4 cuboctahedra. The Cu(1)-Cu(3) bond length is 2.57 Å. Both Cu(1)-Cu(2) bond lengths are 2.78 Å. All Cu(1)-Cu(1) bond lengths are 2.68 Å. There are a spread of Cu(1)-Sn(1) bond distances ranging from 2.62-2.71 Å. In the second Cu site, Cu(2) is bonded in a 12-coordinate geometry to two equivalent Sr(1), one Cu(3), two equivalent Cu(1), three equivalent Cu(2), and four equivalent Sn(1) atoms. The Cu(2)-Cu(3) bond length is 2.63 Å. There are two shorter (2.59 Å) and one longer (2.97 Å) Cu(2)-Cu(2) bond length. There are two shorter (2.76 Å) and two longer (2.80 Å) Cu(2)-Sn(1) bond lengths. In the third Cu site, Cu(3) is bonded to four equivalent Cu(1), four equivalent Cu(2), and four equivalent Sn(1) atoms to form a mixture of face and corner-sharing CuCu8Sn4 cuboctahedra. All Cu(3)-Sn(1) bond lengths are 2.76 Å. Sn(1) is bonded in a 11-coordinate geometry to two equivalent Sr(1), one Cu(3), four equivalent Cu(1), and four equivalent Cu(2) atoms.