Materials Data on Cd2Ge7O16 by Materials Project
Cd2Ge7O16 crystallizes in the tetragonal P-4b2 space group. The structure is three-dimensional. Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.28–2.55 Å. There are three inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent GeO6 octahedra and corners with two equivalent GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–62°. There is two shorter (1.78 Å) and two longer (1.80 Å) Ge–O bond length. In the second Ge4+ site, Ge4+ is bonded to six O2- atoms to form corner-sharing GeO6 octahedra. There are a spread of Ge–O bond distances ranging from 1.88–1.96 Å. In the third Ge4+ site, Ge4+ is bonded to four equivalent O2- atoms to form corner-sharing GeO4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. All Ge–O bond lengths are 1.79 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cd2+ and two Ge4+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Cd2+ and two Ge4+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Ge4+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Cd2+ and two Ge4+ atoms.