Octadecane is a straight-chain hydrocarbon with the chemical formula C18H38. It consists of 18 carbon atoms and is part of the alkane family, which are saturated hydrocarbons. Octadecane is a solid at room temperature and is commonly found in various natural sources, including certain types of waxes and oils. This compound is often used in scientific research and industrial applications, such as in the production of candles and as a phase change material for thermal energy storage. Its properties make it useful in studies related to thermodynamics and material science.