A silicone (or polysiloxane) is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, cooking utensils, adhesives, lubricants, medicine, and thermal and electrical insulation. Some common forms include silicone oil, grease, rubber, resin, and caulk.
The history of silicone begins with F. S. Kipping creating the term silicone in 1901 to describe the combination of polydiphenylsiloxane, Ph2SiO (Ph denoting phenyl, C6H5), by analogy with the formula of the ketone benzophenone, Ph2CO. His term was originally silicoketone. The scientist knew that polydiphenylsiloxane is polymeric, whereas benzophenone is monomeric and noted the contrasting properties of Ph2SiO and Ph2CO. However, discovering the structural differences between Kipping's molecules and the ketones means that silicone is no longer the correct term, although it remains in common usage. Siloxane is the preferred term used in chemistry today.
Silicone is often confused with silicon, but they are two distinct substances. Silicon is a chemical element. Silicone is a compound that contains silicon, carbon, hydrogen, oxygen, and other kinds of atoms. This article explains what silicone is, the composition of silicone, how it is made, what silicone is used for, the properties and types, and whether or not silicone is safe for the environment.