Phosphorus

Phosphorus was a chemical element that was present in flares as a key ingredient. Luke Skywalker had the phosphorus-laden flares installed on the Desert Jewel on Rodia and used it to try and drive a pirate's heat seeking missiles away from him and Nakari.

Text and facts from the “Phosphorus” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.