Materials Data on Cs3AlGe2O7 by Materials Project
Cs3AlGe2O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 2.95–3.63 Å. In the second Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cs–O bond distances ranging from 3.20–3.43 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent GeO4 tetrahedra. There is two shorter (1.77 Å) and two longer (1.78 Å) Al–O bond length. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO4 tetrahedra and corners with two equivalent AlO4 tetrahedra. There are a spread of Ge–O bond distances ranging from 1.73–1.83 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to four equivalent Cs1+ and two equivalent Ge4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three Cs1+, one Al3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three equivalent Cs1+, one Al3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to five Cs1+ and one Ge4+ atom.