Computer graphics representation of a butane molecule (chemical formula C4H10). The molecule consists of a zig-zag chain of four carbon atoms (yellow), each with several hydrogen atoms attached (white). The carbon atoms at the ends of the chain have three hydrogen atoms whereas the inner carbon atoms have only two. Variations occur in the way in which the atoms of butane are arranged in relation to each other. These are called conformations and vary between the extremes of eclipsed and staggered forms. In the type of staggered form shown here (known as gauche), the atoms are arranged far apart, coinciding with a low energy value & increased molecular stability.