Ba(OH)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 13-coordinate geometry to one H(1), one H(2), one H(4), two equivalent H(3), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one H(1), one H(2), one H(3), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Ba(1), one Ba(2), and one O(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one Ba(1), one Ba(2), and one O(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one O(3) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one Ba(1) and one O(4) atom. There are four inequivalent O sites. In the first O site, O(3) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(3) atom. In the second O site, O(4) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(4) atom. In the third O site, O(1) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(1) atom. In the fourth O site, O(2) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(2) atom.
Ba(OH)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 13-coordinate geometry to one H(1), one H(2), one H(4), two equivalent H(3), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ba(1)-H(1) bond length is 2.79 Å. The Ba(1)-H(2) bond length is 2.69 Å. The Ba(1)-H(4) bond length is 2.75 Å. There is one shorter (2.89 Å) and one longer (2.97 Å) Ba(1)-H(3) bond length. There is one shorter (2.71 Å) and one longer (2.90 Å) Ba(1)-O(1) bond length. There is one shorter (2.73 Å) and one longer (2.92 Å) Ba(1)-O(2) bond length. There is one shorter (2.65 Å) and one longer (2.91 Å) Ba(1)-O(3) bond length. There is one shorter (2.81 Å) and one longer (3.06 Å) Ba(1)-O(4) bond length. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one H(1), one H(2), one H(3), two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ba(2)-H(1) bond length is 2.96 Å. The Ba(2)-H(2) bond length is 2.85 Å. The Ba(2)-H(3) bond length is 3.01 Å. There is one shorter (2.88 Å) and one longer (3.01 Å) Ba(2)-O(1) bond length. There is one shorter (2.77 Å) and one longer (2.94 Å) Ba(2)-O(2) bond length. There is one shorter (2.97 Å) and one longer (3.33 Å) Ba(2)-O(3) bond length. There is one shorter (2.69 Å) and one longer (2.80 Å) Ba(2)-O(4) bond length. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Ba(1), one Ba(2), and one O(1) atom. The H(1)-O(1) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one Ba(1), one Ba(2), and one O(2) atom. The H(2)-O(2) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one O(3) atom. The H(3)-O(3) bond length is 0.97 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one Ba(1) and one O(4) atom. The H(4)-O(4) bond length is 0.98 Å. There are four inequivalent O sites. In the first O site, O(3) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(3) atom. In the second O site, O(4) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(4) atom. In the third O site, O(1) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(1) atom. In the fourth O site, O(2) is bonded in a single-bond geometry to two equivalent Ba(1), two equivalent Ba(2), and one H(2) atom.