chlorosulfonic acid

[klawr-oh-suhl-fon-ik, klohr-, klawr-, klohr-]
  1. a colorless or yellowish, highly corrosive, pungent liquid, HClO3S, usually produced by treating sulfur trioxide with hydrogen chloride: used in organic synthesis to introduce the sulfonyl chloride group, =SO2Cl.

Origin of chlorosulfonic acid Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018