HI3O8 crystallizes in the monoclinic P2_1/c space group. H(1) is bonded in a single-bond geometry to one O(6) atom. There are eight inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one I(1) and one I(2) atom. In the second O site, O(6) is bonded in a distorted single-bond geometry to one H(1) and one I(3) atom. In the third O site, O(7) is bonded in a distorted bent 120 degrees geometry to one I(1) and one I(3) atom. In the fourth O site, O(8) is bonded in a distorted single-bond geometry to one I(2) and one I(3) atom. In the fifth O site, O(1) is bonded in a distorted bent 150 degrees geometry to one I(1) and one I(2) atom. In the sixth O site, O(2) is bonded in a single-bond geometry to one I(1) atom. In the seventh O site, O(3) is bonded in a distorted bent 120 degrees geometry to one I(2) and one I(3) atom. In the eighth O site, O(4) is bonded in a distorted single-bond geometry to one I(2) and one I(3) atom. There are three inequivalent I sites. In the first I site, I(1) is bonded in a 3-coordinate geometry to one O(1), one O(2), one O(5), and one O(7) atom. In the second I site, I(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(8) atom. In the third I site, I(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(6), one O(7), and one O(8) atom.
HI3O8 crystallizes in the monoclinic P2_1/c space group. H(1) is bonded in a single-bond geometry to one O(6) atom. The H(1)-O(6) bond length is 1.01 Å. There are eight inequivalent O sites. In the first O site, O(5) is bonded in a bent 120 degrees geometry to one I(1) and one I(2) atom. The O(5)-I(1) bond length is 1.99 Å. The O(5)-I(2) bond length is 2.00 Å. In the second O site, O(6) is bonded in a distorted single-bond geometry to one H(1) and one I(3) atom. The O(6)-I(3) bond length is 1.93 Å. In the third O site, O(7) is bonded in a distorted bent 120 degrees geometry to one I(1) and one I(3) atom. The O(7)-I(1) bond length is 2.58 Å. The O(7)-I(3) bond length is 1.82 Å. In the fourth O site, O(8) is bonded in a distorted single-bond geometry to one I(2) and one I(3) atom. The O(8)-I(2) bond length is 2.65 Å. The O(8)-I(3) bond length is 1.83 Å. In the fifth O site, O(1) is bonded in a distorted bent 150 degrees geometry to one I(1) and one I(2) atom. The O(1)-I(1) bond length is 1.84 Å. The O(1)-I(2) bond length is 2.35 Å. In the sixth O site, O(2) is bonded in a single-bond geometry to one I(1) atom. The O(2)-I(1) bond length is 1.80 Å. In the seventh O site, O(3) is bonded in a distorted bent 120 degrees geometry to one I(2) and one I(3) atom. The O(3)-I(2) bond length is 1.82 Å. The O(3)-I(3) bond length is 2.53 Å. In the eighth O site, O(4) is bonded in a distorted single-bond geometry to one I(2) and one I(3) atom. The O(4)-I(2) bond length is 1.82 Å. The O(4)-I(3) bond length is 2.61 Å. There are three inequivalent I sites. In the first I site, I(1) is bonded in a 3-coordinate geometry to one O(1), one O(2), one O(5), and one O(7) atom. In the second I site, I(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(8) atom. In the third I site, I(3) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(6), one O(7), and one O(8) atom.