Ethene

Ethene, a.k.a. ethylene, consists of two carbons and four hydrogens. The two carbons make double bondings. Ethene is an unsaturated hydrocarbon.

http://wiki.rozeta.com.pl/img/taw/eten.png

(The bondings are not in the right angles)

From ethene by polymerization the popular plastic polyethene can be made.