CCl3.NO2

from The Collaborative International Dictionary of English v.0.48

Chlorpicrin \Chlor`pi"crin\, n. (Chem.)
   A heavy, colorless liquid, {CCl3.NO2}, of a strong pungent
   odor, obtained by subjecting picric acid to the action of
   chlorine. [Written also {chloropikrin}.]
   [1913 Webster]