The material exists as the sulfosalt mineral antimonselite (IMA symbol: Atm[2]), which crystallizes in an orthorhombic space group.

[3] In this compound, antimony has a formal oxidation state +3 and selenium −2.

The bonding in this compound has covalent character as evidenced by the black color and semiconducting properties of this and related materials.

[4] The low-frequency dielectric constant (ε0) has been measured to be 133 along the c axis of the crystal at room temperature, which is unusually large.

[6] The compound may be formed by the reaction of antimony with selenium and has a melting point of 885 K.[4] Sb2Se3 is now being actively explored for application thin-film solar cells.