Materials Data on Cu2GeTe3 by Materials Project

Ge1Cu2Te3 is Enargite-like structured and crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional. there are three inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with five equivalent GeTe4 tetrahedra and corners with seven CuTe4 tetrahedra. There are a spread of Cu–Te bond distances ranging from 2.56–2.59 Å. In the second Cu1+ site, Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with six CuTe4 tetrahedra and corners with six equivalent GeTe4 tetrahedra. There are two shorter (2.58 Å) and two longer (2.59 Å) Cu–Te bond lengths. In the third Cu1+ site, Cu1+ is bonded to four Te2- atoms to form CuTe4 tetrahedra that share corners with four equivalent GeTe4 tetrahedra and corners with eight CuTe4 tetrahedra. All Cu–Te bond lengths are 2.57 Å. Ge4+ is bonded to four Te2- atoms to form GeTe4 tetrahedra that share corners with two equivalent GeTe4 tetrahedra and corners with ten CuTe4 tetrahedra. There are a spread of Ge–Te bond distances ranging from 2.66–2.75 Å. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to two Cu1+ and two equivalent Ge4+ atoms to form corner-sharing TeCu2Ge2 tetrahedra. In the second Te2- site, Te2- is bonded to three Cu1+ and one Ge4+ atom to form corner-sharing TeCu3Ge tetrahedra. In the third Te2- site, Te2- is bonded to three Cu1+ and one Ge4+ atom to form corner-sharing TeCu3Ge tetrahedra.