Ba2B2O5 crystallizes in the triclinic P-1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(3), two equivalent O(2), two equivalent O(5), and three equivalent O(1) atoms to form distorted edge-sharing BaO8 hexagonal bipyramids. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to one O(2), two equivalent O(3), and three equivalent O(4) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(5) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2), one O(4), and one O(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one B(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Ba(2), and one B(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Ba(2) and one B(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one B(1), and one B(2) atom.
Ba2B2O5 crystallizes in the triclinic P-1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(3), two equivalent O(2), two equivalent O(5), and three equivalent O(1) atoms to form distorted edge-sharing BaO8 hexagonal bipyramids. The Ba(1)-O(3) bond length is 2.87 Å. There is one shorter (2.69 Å) and one longer (2.96 Å) Ba(1)-O(2) bond length. There is one shorter (2.84 Å) and one longer (3.12 Å) Ba(1)-O(5) bond length. There are a spread of Ba(1)-O(1) bond distances ranging from 2.64-2.78 Å. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to one O(2), two equivalent O(3), and three equivalent O(4) atoms. The Ba(2)-O(2) bond length is 2.63 Å. There is one shorter (2.68 Å) and one longer (2.73 Å) Ba(2)-O(3) bond length. There are a spread of Ba(2)-O(4) bond distances ranging from 2.70-2.76 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(3), and one O(5) atom. The B(1)-O(1) bond length is 1.36 Å. The B(1)-O(3) bond length is 1.35 Å. The B(1)-O(5) bond length is 1.43 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(2), one O(4), and one O(5) atom. The B(2)-O(2) bond length is 1.36 Å. The B(2)-O(4) bond length is 1.36 Å. The B(2)-O(5) bond length is 1.44 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one B(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(2), two equivalent Ba(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Ba(2), and one B(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Ba(2) and one B(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one B(1), and one B(2) atom.