Diesel does not have a specific formula because it is not a single compound. Instead, diesel is made of a mix of saturated hydrocarbons and aromatic hydrocarbons.
Diesel primarily consists of stable molecules such as C12H22, C13H24 and C12H24. Chemists sometime describe diesel as having an average chemical composition of C12H23. However, this is only a general chemical description; it does not accurately reflect diesel's chemical composition. There are two major types of diesel fuel: standard diesel fuel, which is derived from crude oil, and biodiesel, which is derived from agricultural products. Biodiesel is a cleaner alternative to standard fuel.