Unsaturated Fatty Acids are illustrated with, starting at top left and moving clockwise, oleic (9-octadecenoic, 18:1), lenoleic (9,12-octadecadienoic, 18:2), lenolenic (9,12,15-octadecatrienoic, 18:3) and arachidonic (5,8,11,14-eicosatetraenoic, 20:4) acids. As with nearly all naturally occuring unsaturated fatty acids all the carbon-carbon double bonds have the cis configuration, and this configurations produces a curvature in the carbon chain which increases as the number of double bonds in the chain increase. All four structures have the all staggered conformation and as shown with the saturated fatty acids the energy available at room temperature can form a large number of conformations that are not as symmetrical as the all staggered.