Materials Data on K2Ca2MgH2(SO4)4 by Materials Project

Abstract

K2Ca2MgH2(SO4)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. K1+ is bonded in a 11-coordinate geometry to one H1+ and ten O2- atoms. The K–H bond length is 2.90 Å. There are a spread of K–O bond distances ranging from 2.75–3.23 Å. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.77 Å. Mg2+ is bonded to two equivalent H1+ and four O2- atoms to form MgH2O4 octahedra that share corners with four SO4 tetrahedra. Both Mg–H bond lengths are 2.20 Å. There are two shorter (1.98 Å) and two longer (2.09 Å) Mg–O bond lengths. H1+ is bonded in a water-like geometry to one K1+ and one Mg2+ atom. There are two inequivalent S+5.50+ sites. In the first S+5.50+ site, S+5.50+ is bonded to four O2- atoms to form SO4 tetrahedra that share a cornercorner with one MgH2O4 octahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of S–O bond distances ranging from 1.48–1.53 Å. In the second S+5.50+ site, S+5.50+ is bonded to four O2- atoms to form SO4 tetrahedra that share a cornercorner with one MgH2O4 octahedra. The corner-sharing octahedral tilt angles are 31°. There are a spread of S–O bond distances ranging from 1.47–1.52 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+, one Mg2+, and one S+5.50+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Ca2+, and one S+5.50+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ca2+, and one S+5.50+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, one Ca2+, one Mg2+, and one S+5.50+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and one S+5.50+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Ca2+, and one S+5.50+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, one Ca2+, and one S+5.50+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, one Ca2+, and one S+5.50+ atom.