Eu2CuSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. Eu(1) is bonded to three equivalent Cu(1), three equivalent Si(1), three equivalent Si(2), and three equivalent Si(3) atoms to form a mixture of edge and face-sharing EuCu3Si9 cuboctahedra. Cu(1) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Si(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Cu(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Si(1) atoms.
Eu2CuSi3 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P-6m2 space group. Eu(1) is bonded to three equivalent Cu(1), three equivalent Si(1), three equivalent Si(2), and three equivalent Si(3) atoms to form a mixture of edge and face-sharing EuCu3Si9 cuboctahedra. All Eu(1)-Cu(1) bond lengths are 3.17 Å. All Eu(1)-Si(1) bond lengths are 3.26 Å. All Eu(1)-Si(2) bond lengths are 3.17 Å. All Eu(1)-Si(3) bond lengths are 3.26 Å. Cu(1) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Si(2) atoms. All Cu(1)-Si(2) bond lengths are 2.35 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Si(3) atoms. All Si(1)-Si(3) bond lengths are 2.35 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Cu(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to six equivalent Eu(1) and three equivalent Si(1) atoms.