Au3S crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Au+0.67+ is bonded in a see-saw-like geometry to four equivalent S2- atoms. There are two shorter (2.94 Å) and two longer (2.95 Å) Au–S bond lengths. S2- is bonded to twelve equivalent Au+0.67+ atoms to form a mixture of corner and face-sharing SAu12 cuboctahedra.