Materials Data on H2S2O7 by Materials Project
H2S2O7 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four disulfuric acid molecules, four hydrogen peroxide molecules, four sulfino hydrogen sulfite molecules, and four H2S2O7 clusters. In each H2S2O7 cluster, there are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.66 Å) H–O bond length. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form corner-sharing SO4 tetrahedra. There are a spread of S–O bond distances ranging from 1.43–1.69 Å. In the second S6+ site, S6+ is bonded to four O2- atoms to form corner-sharing SO4 tetrahedra. There are a spread of S–O bond distances ranging from 1.42–1.63 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two S6+ atoms. In the second O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one H1+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one H1+ and one S6+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one H1+ and one S6+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one S6+ atom.