Er5Si3 crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 5-coordinate geometry to five equivalent Si(1) atoms. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to six equivalent Si(1) atoms. Si(1) is bonded in a 9-coordinate geometry to four equivalent Er(2) and five equivalent Er(1) atoms.
Er5Si3 crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 5-coordinate geometry to five equivalent Si(1) atoms. There are a spread of Er(1)-Si(1) bond distances ranging from 2.87-3.38 Å. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to six equivalent Si(1) atoms. All Er(2)-Si(1) bond lengths are 3.00 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent Er(2) and five equivalent Er(1) atoms.