SEX is the official abbreviation of sodium ethyl xanthate, which is a flotation agent used in the mining industry. Apparently you can get SEX in both solid and liquid forms . . .

Lots of other fun ones on this page, too. Such as:

Dickite
Moronic Acid
Cummingtonite
Phthalic Acid

(Thanks to BillyGoto for the link to this one!)

Molecules with Silly or Unusual Names