DOE OSTI2020
NaGaAl12O50(SO4)4 crystallizes in the cubic F-43m space group. The structure is three-dimensional and consists of sixteen sulfuric acid molecules and one NaGaAl12O50 framework. In the NaGaAl12O50 framework, Na is bonded in a 12-coordinate geometry to twelve equivalent O atoms. All Na–O bond lengths are 3.05 Å. Ga is bonded in a body-centered cubic geometry to eight O atoms. There are four shorter (2.22 Å) and four longer (2.41 Å) Ga–O bond lengths. Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent OGaO3 tetrahedra and edges with three equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.05 Å. There are six inequivalent O sites. In the first O site, O is bonded to one Ga and three equivalent O atoms to form distorted OGaO3 tetrahedra that share corners with six equivalent AlO6 octahedra and corners with seven OGaO3 tetrahedra. The corner-sharing octahedral tilt angles are 68°. All O–O bond lengths are 1.69 Å. In the second O site, O is bonded in a distorted trigonal planar geometry to two equivalent Al and one O atom. The O–O bond length is 1.43 Å. In the third O site, O is bonded in a water-like geometry to two equivalent O atoms. In the fourth O site, O is bonded in a distorted water-like geometry to two equivalent Al and one O atom. In the fifth O site, O is bonded to one Ga and three equivalent Al atoms to form corner-sharing OAl3Ga tetrahedra. In the sixth O site, O is bonded in a single-bond geometry to one Na and one Al atom.