Polycarbonate PC plastic is formed by a condensation polymerization resulting in a carbon that is bonded to three oxygens. The most common system for this polymerization is formed by a reaction of bisphenol A and phosgene. Applications of polycarbonate plastic are almost always those which take advantage of its uniquely high impact strength and its exceptional clarity. These unique properties of polycarbonate PC plastic have resulted in applications such as bulletproof windows, break resistant lenses, compact discs, etc. More recently however, additional interest has resulted because of the low flammability of polycarbonate plastic.