It is a colourless gas and condenses to give a roughly dark red coloured solid that is unstable at room temperature.

S2O occurs rarely in natural atmospheres, but can be made by a variety of laboratory procedures.

He discovered that the gas could survive for hours at single digit pressures of mercury in clean glass, but it decomposed near 30 mmHg (4 kPa).

Also 5,6-di-tert-butyl-2,3,7-trithiabicyclo[2.2.1]hept-5-ene 2-endo-7-endo-dioxide decomposes upon heating with release of S2O:[15] Triphenylphosphine sulfide reacts with sulfinyltosylimide to give S2O and tosyltriphenylphosphinylamide:[16] Volcanoes on Io produce substantial quantities of S2O.

[19] Disulfur monoxide occurs as a ligand bound to transition metals, typically with hapticity 2.