Sulfinylmethane or sulfine is an organic compound with molecular formula H2CSO.

Sulfines are chemical compounds with the general structure XY=SO.

The parent sulfine H2CSO is very labile, whereas substituted derivatives are more conveniently isolated.

One route is a variant of ketene synthesis, in which a sulfinyl halide reacts with a hindered base.

For example, syn-propanethial-S-oxide, responsible for eye-watering effects of cutting onions, is produced so from allicin.