Cu2FeGeS4 is Stannite structured and crystallizes in the tetragonal I-42m space group. Fe(1) is bonded to four equivalent S(1) atoms to form FeS4 tetrahedra that share corners with four equivalent Ge(1)S4 tetrahedra and corners with eight equivalent Cu(1)S4 tetrahedra. Cu(1) is bonded to four equivalent S(1) atoms to form CuS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with four equivalent Cu(1)S4 tetrahedra, and corners with four equivalent Ge(1)S4 tetrahedra. Ge(1) is bonded to four equivalent S(1) atoms to form GeS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra and corners with eight equivalent Cu(1)S4 tetrahedra. S(1) is bonded to one Fe(1), two equivalent Cu(1), and one Ge(1) atom to form corner-sharing SFeCu2Ge tetrahedra.
Cu2FeGeS4 is Stannite structured and crystallizes in the tetragonal I-42m space group. Fe(1) is bonded to four equivalent S(1) atoms to form FeS4 tetrahedra that share corners with four equivalent Ge(1)S4 tetrahedra and corners with eight equivalent Cu(1)S4 tetrahedra. All Fe(1)-S(1) bond lengths are 2.30 Å. Cu(1) is bonded to four equivalent S(1) atoms to form CuS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with four equivalent Cu(1)S4 tetrahedra, and corners with four equivalent Ge(1)S4 tetrahedra. All Cu(1)-S(1) bond lengths are 2.29 Å. Ge(1) is bonded to four equivalent S(1) atoms to form GeS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra and corners with eight equivalent Cu(1)S4 tetrahedra. All Ge(1)-S(1) bond lengths are 2.30 Å. S(1) is bonded to one Fe(1), two equivalent Cu(1), and one Ge(1) atom to form corner-sharing SFeCu2Ge tetrahedra.