Sentence:  It appears possible to set a lower limit of about * * f for the activation energy of the abstraction of a chlorine atom from a <WSD>carbon</WSD> tetrachloride molecule by a chlorine atom to form * * f radical . 
Meaning of the word marked with <WSD> tags:  a colorless nonflammable liquid used as a solvent for fats and oils; because of its toxicity its use as a cleaning fluid or fire extinguisher has declined