Sr5Si3 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to two equivalent Si(2) and three equivalent Si(1) atoms to form a mixture of distorted corner, edge, and face-sharing SrSi5 trigonal bipyramids. In the second Sr site, Sr(2) is bonded in a square co-planar geometry to four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sr(2), six equivalent Sr(1), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to eight equivalent Sr(1) atoms.
Sr5Si3 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to two equivalent Si(2) and three equivalent Si(1) atoms to form a mixture of distorted corner, edge, and face-sharing SrSi5 trigonal bipyramids. Both Sr(1)-Si(2) bond lengths are 3.43 Å. There are two shorter (3.27 Å) and one longer (3.30 Å) Sr(1)-Si(1) bond length. In the second Sr site, Sr(2) is bonded in a square co-planar geometry to four equivalent Si(1) atoms. All Sr(2)-Si(1) bond lengths are 3.29 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sr(2), six equivalent Sr(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.44 Å. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to eight equivalent Sr(1) atoms.