Materials Data on Ca2H2S2O7 by Materials Project
Ca2H2S2O7 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.74 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. S4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.54 Å) and one longer (1.56 Å) S–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one S4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one S4+ atom. In the third O2- site, O2- is bonded in a water-like geometry to two equivalent Ca2+ and two equivalent H1+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Ca2+ and one S4+ atom.