A single bond is a chemical bond between two elements in which two electrons are shared. Single bonds can occur in many different types of chemical attractions, including covalent, ionic, and hydrogen bonding.
A model compound displaying single bonds is that of CH4 - in which four single bonds stem from central carbon atom to four hydrogen atoms. In methane, the four single bonds are equally distanced from the central atom. However, in certain cases (see H2O), the angles of bonding are affected by lone pairs of electrons on the central atom. The lone pairs repel the two electrons in each single bond, thereby altering the bond angle.