Task: Text Categorization
Input (English): The allylation of nucleophiles with allylic halides is one example of the Tsuji-Trost reactions catalyzed by this element. Eaborn discovered that it can catalyze the reaction of aryl halides with hexa-n-butyldistannane, and more broadly it underlies the reaction of vinylic and aromatic systems with organostannanes in the Kosugi-Migita-Stille coupling. Also used for the coupling of alkenes and either halides or pseudohalides in the Mizoroki-Heck reactions, this element's chloride is reduced by calcium carbonate before lead acetate is added in the creation of a catalyst which is named for Lindlar. For 10 points, name this element, the least dense of the platinum group metals.
Output (English): Science