The Collaborative International Dictionary of English v.0.48:

Brompicrin \Brom*pi"crin\, n. [G. brompikrin; brom bromine +
   pikrins[aum]ure picric acid.] (Chem.)
   A pungent colorless explosive liquid, CNO2Br3, analogous to
   and resembling chlorpicrin. [Spelt also brompikrin.]
   [1913 Webster] Brompton's cocktail
   Brompton mixture
   Brompton's mixture