Materials Data on Al2Ge2O7 by Materials Project
Al2Ge2O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Al3+ is bonded to five O2- atoms to form AlO5 trigonal bipyramids that share corners with five equivalent GeO4 tetrahedra and edges with two equivalent AlO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.75–1.94 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO4 tetrahedra and corners with five equivalent AlO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.72–1.80 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Al3+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one Ge4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ge4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one Ge4+ atom.