Materials Data on Na2CaAl10(H3O10)2 by Materials Project

Abstract

Na2CaAl10(HO10)2(H2)2 crystallizes in the orthorhombic Pmna space group. The structure is three-dimensional and consists of eight hydrogen molecules and one Na2CaAl10(HO10)2 framework. In the Na2CaAl10(HO10)2 framework, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.37 Å) and two longer (2.42 Å) Na–O bond lengths. Ca2+ is bonded to two equivalent H1+ and six O2- atoms to form distorted CaH2O6 hexagonal bipyramids that share corners with four equivalent AlO4 tetrahedra and edges with four equivalent AlO4 tetrahedra. Both Ca–H bond lengths are 2.65 Å. There are two shorter (2.31 Å) and four longer (2.95 Å) Ca–O bond lengths. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. All Al–O bond lengths are 1.75 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four AlO4 tetrahedra and an edgeedge with one CaH2O6 hexagonal bipyramid. There are a spread of Al–O bond distances ranging from 1.75–1.77 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one CaH2O6 hexagonal bipyramid and corners with four AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.75–1.78 Å. H1+ is bonded in a single-bond geometry to one Ca2+ atom. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two Al3+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Na1+ and two equivalent Al3+ atoms to form distorted edge-sharing ONa2Al2 trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and two Al3+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Al3+ atoms.