YbEu(AuSi)4 crystallizes in the tetragonal P4/mmm space group. Yb(1) is bonded in a 16-coordinate geometry to eight equivalent Au(1) and eight equivalent Si(2) atoms. Eu(1) is bonded in a 16-coordinate geometry to eight equivalent Au(1) and eight equivalent Si(1) atoms. Au(1) is bonded in a 4-coordinate geometry to two equivalent Yb(1), two equivalent Eu(1), two equivalent Si(1), and two equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Eu(1), four equivalent Au(1), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Yb(1), four equivalent Au(1), and one Si(2) atom.
YbEu(AuSi)4 crystallizes in the tetragonal P4/mmm space group. Yb(1) is bonded in a 16-coordinate geometry to eight equivalent Au(1) and eight equivalent Si(2) atoms. All Yb(1)-Au(1) bond lengths are 3.33 Å. All Yb(1)-Si(2) bond lengths are 3.33 Å. Eu(1) is bonded in a 16-coordinate geometry to eight equivalent Au(1) and eight equivalent Si(1) atoms. All Eu(1)-Au(1) bond lengths are 3.37 Å. All Eu(1)-Si(1) bond lengths are 3.33 Å. Au(1) is bonded in a 4-coordinate geometry to two equivalent Yb(1), two equivalent Eu(1), two equivalent Si(1), and two equivalent Si(2) atoms. Both Au(1)-Si(1) bond lengths are 2.60 Å. Both Au(1)-Si(2) bond lengths are 2.58 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Eu(1), four equivalent Au(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.33 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Yb(1), four equivalent Au(1), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.32 Å.