[6] Sulfur monoxide (SO) converts to disulfur dioxide (S2O2) spontaneously and reversibly.

[5] Another laboratory procedure is to react oxygen atoms with carbonyl sulfide or carbon disulfide vapour.

[10] Disulfur dioxide is formed transiently when hydrogen sulfide and oxygen undergo flash photolysis.

[11] A branched isomer isoelectronic to SO3, S=SO2, is believed to form during the thermal decomposition of cyclic vicinal alkyl thiosulfites.

[7] Disulfur dioxide absorbs at 320–400 nm, as observed of the Venusian atmosphere,[13] and is believed to have contributed to the greenhouse effect on that planet.

[20] There is some evidence that disulfur dioxide may be a small component in the atmosphere of Venus, and that it may substantially contribute of the planet's severe greenhouse effect.