EuCu9Sn4 is Bergman Structure: Mg32(Al,Zn)49 Bergman-like structured and crystallizes in the tetragonal I4/mcm space group. Eu(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 in a 12-coordinate geometry to two equivalent Eu(1), one Cu(3), two equivalent Cu(2), three equivalent Cu(1), and four equivalent Sn(1) atoms. In the second Cu site, Cu(2) is bonded in a 12-coordinate geometry to two equivalent Eu(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 in a cuboctahedral geometry to four equivalent Cu(1), four equivalent Cu(2), and four equivalent Sn(1) atoms. Sn(1) is bonded in a 11-coordinate geometry to two equivalent Eu(1), one Cu(3), four equivalent Cu(1), and four equivalent Cu(2) atoms.
EuCu9Sn4 is Bergman Structure: Mg32(Al,Zn)49 Bergman-like structured and crystallizes in the tetragonal I4/mcm space group. Eu(1) is bonded in a 24-coordinate geometry to eight equivalent Cu(1), eight equivalent Cu(2), and eight equivalent Sn(1) atoms. All Eu(1)-Cu(1) bond lengths are 3.65 Å. All Eu(1)-Cu(2) bond lengths are 3.60 Å. All Eu(1)-Sn(1) bond lengths are 3.52 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 12-coordinate geometry to two equivalent Eu(1), one Cu(3), two equivalent Cu(2), three equivalent Cu(1), and four equivalent Sn(1) atoms. The Cu(1)-Cu(3) bond length is 2.54 Å. Both Cu(1)-Cu(2) bond lengths are 2.76 Å. There is one shorter (2.65 Å) and two longer (2.67 Å) Cu(1)-Cu(1) bond lengths. There are a spread of Cu(1)-Sn(1) bond distances ranging from 2.60-2.70 Å. In the second Cu site, Cu(2) is bonded in a 12-coordinate geometry to two equivalent Eu(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 (2.56 Å) and one longer (2.99 Å) Cu(2)-Cu(2) bond length. There are two shorter (2.75 Å) and two longer (2.79 Å) Cu(2)-Sn(1) bond lengths. In the third Cu site, Cu(3) is bonded in a cuboctahedral geometry to four equivalent Cu(1), four equivalent Cu(2), and four equivalent Sn(1) atoms. All Cu(3)-Sn(1) bond lengths are 2.77 Å. Sn(1) is bonded in a 11-coordinate geometry to two equivalent Eu(1), one Cu(3), four equivalent Cu(1), and four equivalent Cu(2) atoms.