Eu5Si3H crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 4-coordinate geometry to two equivalent Si(1) and four equivalent Si(2) atoms. In the second Eu site, Eu(2) is bonded in a distorted single-bond geometry to two equivalent Si(1), three equivalent Si(2), and one H(1) atom. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to two equivalent Eu(1) and eight equivalent Eu(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Eu(1), six equivalent Eu(2), and one Si(2) atom. H(1) is bonded in a tetrahedral geometry to four equivalent Eu(2) atoms.
Eu5Si3H crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 4-coordinate geometry to two equivalent Si(1) and four equivalent Si(2) atoms. Both Eu(1)-Si(1) bond lengths are 3.61 Å. All Eu(1)-Si(2) bond lengths are 3.13 Å. In the second Eu site, Eu(2) is bonded in a distorted single-bond geometry to two equivalent Si(1), three equivalent Si(2), and one H(1) atom. Both Eu(2)-Si(1) bond lengths are 3.22 Å. There are two shorter (3.10 Å) and one longer (3.21 Å) Eu(2)-Si(2) bond length. The Eu(2)-H(1) bond length is 2.38 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to two equivalent Eu(1) and eight equivalent Eu(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Eu(1), six equivalent Eu(2), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.40 Å. H(1) is bonded in a tetrahedral geometry to four equivalent Eu(2) atoms.