Structural formulas are graphic representations of a molecule, usually taking the form of a skeleton structure where the carbons are in the bends of the lines and the hydrogens connected to the carbons are assumed and not shown. They show what kind of atoms the molecule has, what kind of bonds (single, double, or triple bonds), and their placement (coming out towards you, or into the page, or which way they are going). Showing placement can be important when assigning R or S and E and Z conformations, or different isomers such as diastereomers, stereoisomers, and enantiomers, all of which are important when distinguishing between molecules.