Ethylene is a compound composed of two carbon atoms and four hydrogen atoms, with the two carbon atoms connected by a double bond. It is the simplest olefin, with a molecular formulhttps://www.huaxichemical.com/26734-2/a of CH2=CH2. It is a basic chemical raw material for synthetic fibers, synthetic rubber, synthetic plastics (polyethylene and polyvinyl chloride), and synthetic ethanol (alcohol). It is also used to make vinyl chloride, styrene, ethylene oxide, acetic acid, acetaldehyde, ethanol, and explosives. It exists in small amounts in plants and is a metabolite of plants that can slow down plant growth, promote leaf fall and fruit ripening. It is a colorless, flammable gas at room temperature. The melting point is -169°C and the boiling point is -103.7°C. It is almost insoluble in water, difficult to dissolve in ethanol, and easily soluble in ether and acetone. The bond length of the C=C double bond in the ethylene molecule is 1.33×10-10 meters. The two carbon atoms and four hydrogen atoms in the ethylene molecule are all on the same plane. The bond angle between them is about 120°. The bond energy of the ethylene double bond is 615 kJ/mol. The experimentally measured bond length of the ethane C-C single bond is 1.54×10-10 meters, and the bond energy is 348 kJ/mol. This shows that the bond energy of the C=C double bond is not twice that of the C-C single bond, but slightly less than twice. Therefore, only less energy is needed to break one of the double bonds. This is the reason why ethylene is active and prone to addition reactions.