Types of Bonds All bonds, in and around an atom, fall into two categories: intermolecular and intramolecular bonds. These two categories can then be further divided into three subcategories; Intramolecular Chemical Bonds – A chemical bond is a connection between atoms through the sharing of electrons through overlapping orbitals. A typical chemical bond will contain two electrons, and one electron will usually originate from each of the atoms involved. The shared electrons do not necessarily have to come from both atoms nor does the number of atoms involved need to be two, 3-centered two-electron bonds exist. This type of bond is the strongest of all three bonds and therefore requires the greatest amount of energy to break - ranging from 151 KJ/mol (II) to 945 KJ/mol (N≡N). There are two types of chemical bonds; Ionic and covalent bonds.Intermolecular Van-Der-Waals – This type of bond is the weakest of the three bonds and originates from the fact that electrons are constantly in motion. Because they don't all move in unison, "wells" appear where there is a net negative and positive charge. These opposite charges then attract each other and, albeit weakly, congregate the molecules together. Since these bonds are based on electrons, the greater the number of electrons in a molecule – and therefore the size of the molecules themselves – the greater these forces. These forces can therefore be divided into two subcategories; London Dispersive forces and dipole-dipole interactions. Hydrogen Bonds – These bonds are strong intermolecular forces, much greater than Van-Der-Waals forces and yet relatively small compared to a chemical bond. A hydrogen bond can range from approximately 5-35 KJ/mol. 'Groups of molecules are held together in specific orientations... in the center of the sheet... FHC, A Structure for Deoxyribose Nucleic Acid, Nature 171, 737-738 (1953)7. Lehninger, Nelson, D.L., Cox, M.M, Principles of Biochemistry, W.H. Freeman and Company, USA, 2013, pages 292-2938. Jeffrey, G.A., An Introduction to Hydrogen Bonding, Oxford University Press, New York, 1997, page 1859. I. David Brown, The Chemical Bond in Inorganic Chemistry, Oxford University Press, New York, 2002 page 2710. I. David Brown, The Chemical Bond in Inorganic Chemistry, Oxford University Press, New York, 2002 page 7711. Desiraju, G.R., Steiner, T., The Weak Hydrogen Bond, Oxford University Press, New York, 1999, pages 412. Friebolin, H. Basic One and two-dimensional NMR spectroscopy, 5th ed. Federal Republic of Germany, 2011, pages 59-6013. Friebolin, H. Basic One- and Two-Dimensional NMR Spectroscopy, 5th ed. Federal Republic of Germany, 2011, p 335