Methylsulfonylmethane (MSM), is an organosulfur compound with the formula (CH3)2SO2. It is also known by several other names: DMSO2, MSM, methylsulfonylmethane and methyl sulfone.  This colourless solid features the sulfone functional group and is considered relatively inert chemically. It occurs naturally in some primitive plants and is present in small amounts in many foods and beverages and it is marketed as a dietary supplement, although its benefits are disputed. Because of its polarity and thermal stability, MSM is used industrially as a high-temperature solvent for both inorganic and organic substances. It is used as a medium in organic synthesis. For example, displacement of aryl chlorides by potassium fluoride can be usefully conducted in molten MSM. With a pKa of 31, it can be deprotonated with sodium amide, and the conjugate base is an effective nucleophile.