Materials Data on Cd2GeAs4 by Materials Project
Cd2GeAs4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Cd2+ is bonded to four As2- atoms to form distorted CdAs4 tetrahedra that share corners with four equivalent GeAs4 tetrahedra, corners with six equivalent CdAs4 tetrahedra, and an edgeedge with one CdAs4 tetrahedra. There are a spread of Cd–As bond distances ranging from 2.72–2.77 Å. Ge4+ is bonded to four As2- atoms to form GeAs4 tetrahedra that share corners with two equivalent AsCd2GeAs tetrahedra and corners with eight equivalent CdAs4 tetrahedra. There are one shorter (2.47 Å) and three longer (2.50 Å) Ge–As bond lengths. There are three inequivalent As2- sites. In the first As2- site, As2- is bonded to four equivalent Cd2+ and one Ge4+ atom to form distorted AsCd4Ge trigonal bipyramids that share corners with ten equivalent AsCd2GeAs tetrahedra and edges with two equivalent AsCd4Ge trigonal bipyramids. In the second As2- site, As2- is bonded to two equivalent Cd2+, one Ge4+, and one As2- atom to form distorted AsCd2GeAs tetrahedra that share a cornercorner with one GeAs4 tetrahedra, corners with four equivalent AsCd2GeAs tetrahedra, and corners with five equivalent AsCd4Ge trigonal bipyramids. The As–As bond length is 2.48 Å. In the third As2- site, As2- is bonded in a 3-coordinate geometry to one Ge4+ and two equivalent As2- atoms.