Materials Data on MgH4S2O9 by Materials Project
MgH4S2O9 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two MgH4S2O9 sheets oriented in the (0, 0, 1) direction. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent SO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.45 Å. There are four 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 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.10 Å) and one longer (1.36 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 22–38°. There are a spread of S–O bond distances ranging from 1.46–1.55 Å. In the second S6+ site, S6+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of S–O bond distances ranging from 1.49–1.84 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one H1+ and one S6+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one S6+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one S6+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one H1+ and one O2- atom. The O–O bond length is 1.46 Å. In the seventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Mg2+, one S6+, and one O2- atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mg2+ and one S6+ atom. In the ninth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms.