Ba3SiO5 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(2) and six equivalent O(1) atoms. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to two equivalent O(2) and eight equivalent O(1) atoms. Si(1) is bonded in a tetrahedral geometry to four equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(2), three equivalent Ba(1), and one Si(1) atom. In the second O site, O(2) is bonded to two equivalent Ba(2) and four equivalent Ba(1) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-31°.
Ba3SiO5 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(2) and six equivalent O(1) atoms. Both Ba(1)-O(2) bond lengths are 2.69 Å. There are two shorter (2.71 Å) and four longer (2.95 Å) Ba(1)-O(1) bond lengths. In the second Ba site, Ba(2) is bonded in a 10-coordinate geometry to two equivalent O(2) and eight equivalent O(1) atoms. Both Ba(2)-O(2) bond lengths are 2.83 Å. All Ba(2)-O(1) bond lengths are 3.06 Å. Si(1) is bonded in a tetrahedral geometry to four equivalent O(1) atoms. All Si(1)-O(1) bond lengths are 1.64 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(2), three equivalent Ba(1), and one Si(1) atom. In the second O site, O(2) is bonded to two equivalent Ba(2) and four equivalent Ba(1) atoms to form corner-sharing OBa6 octahedra. The corner-sharing octahedral tilt angles range from 0-31°.