/klawr"oh sul fon"ik, klohr"-, klawr'-, klohr'-/
a colorless or yellowish, highly corrosive, pungent liquid, HClO 3 S, usually produced by treating sulfur trioxide with hydrogen chloride: used in organic synthesis to introduce the sulfonyl chloride group, =SO 2 Cl.
[ CHLORO- 2 + SULFONIC ACID ]