ethene (C2H4)

Also known as ethylene, the first member of the alkene family ofhydrocarbons. Ethene is a colorless, flammable gas, with a slightly sweetsmell. It burns in air with a luminous flame and forms an explosive mixture with pure oxygen. It combines directly with the halogens, e.g., with chlorineto form 1,2-dichloroethane. With hydrogen it forms ethane. 

Ethene is made by cracking hydrocarbons (notably ethane and propane) from petroleum and is an important raw material for making other organic chemicals, including ethanal, ethanol, ethyl chloride, diethyl ether, and ethane-1,2-diol. It can be polymerized to make polyethene. It is oxidized by air over a silver catalyst to ethylene oxide, a reactive gas used as a fumigant and to make plastics and emulsifiers, and hydrated to ethylene glycol. 

Ethene occurs naturally in plants, in which it serves as a growth substance. It is well known for its ability to stimulate the ripening of fruits.

molecular weight	28.08
melting point	-169.4°C
boiling point	-103.7°C