Conformations of Acyclic Alkanes

Acyclic and cyclic alkanes are continuously in motion, flipping, twisting, bending and rotating externally and internally.  At room temperature, ethane rotates about its sigma bond extremely fast. Each methyl group completing a full 360° rotation roughly every 10⁻¹¹ seconds. This rapid movement creates a variety of different spatial arrangements or conformations. If you could take a lot pictures of a molecule with a very very fast camera you would notice most of the pictures would correspond to conformations of low energy.  Indeed molecules will spend most of their time in low energy stable conformations and much shorter amounts of time in high energy unstable conformations.

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Click the "Start Spin" button below to see what 10 rotations per second looks like.  At room temperature, an ethane molecule's methyl groups rotate 1011 times per second.  The hydrogen atoms are traveling at about 600 m/s.  That's about 0.0002% of the speed of light.  That's crazy fast!