Ba5Si3 crystallizes in the tetragonal P4/ncc space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to two equivalent Si(2) and three equivalent Si(1) atoms to form a mixture of distorted face, corner, and edge-sharing BaSi5 trigonal bipyramids. In the second Ba site, Ba(2) is bonded to one Si(2) and four equivalent Si(1) atoms to form a mixture of distorted face, corner, and edge-sharing BaSi5 square pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Ba(2), six equivalent Ba(1), and one Si(1) atom. In the second Si site, Si(2) is bonded in a distorted q6 geometry to one Ba(2) and eight equivalent Ba(1) atoms.
Ba5Si3 crystallizes in the tetragonal P4/ncc space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to two equivalent Si(2) and three equivalent Si(1) atoms to form a mixture of distorted face, corner, and edge-sharing BaSi5 trigonal bipyramids. There is one shorter (3.57 Å) and one longer (3.68 Å) Ba(1)-Si(2) bond length. There are a spread of Ba(1)-Si(1) bond distances ranging from 3.39-3.51 Å. In the second Ba site, Ba(2) is bonded to one Si(2) and four equivalent Si(1) atoms to form a mixture of distorted face, corner, and edge-sharing BaSi5 square pyramids. The Ba(2)-Si(2) bond length is 3.48 Å. All Ba(2)-Si(1) bond lengths are 3.55 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Ba(2), six equivalent Ba(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.45 Å. In the second Si site, Si(2) is bonded in a distorted q6 geometry to one Ba(2) and eight equivalent Ba(1) atoms.