Van der Waals forces Another set of intermolecular interactions is the Van der Waals forces, which are primarily associated with non-polar molecules. They arise because of short-lived induced dipole moments which occur even in non-polar molecules. These are also sometimes referred to as London Dispersion Forces. The repulsive forces between Read more…
Hydrogen Bonding A particularly important type of dipole-dipole interaction is hydrogen bonding. It’s the main reason for the stability of the double-helix secondary structure of DNA, the unusual phase diagram of water, and the secondary structure of proteins in our bodies. Strictly speaking, hydrogen bonds are a special case of Read more…
Ion-Dipole Interactions and Hydrophilicity Ion-dipole forces are generally stronger than dipole-dipole interactions because at least one of their participants is an ion, which means it has a net electric charge, whereas dipole-dipole forces involve polar molecules with no net electric charge. These interactions explain why ionic compounds tend to be Read more…
Dipole-dipole interactions Many covalently bonded molecules have a net neutral electric charge, but do not distribute their charge evenly. Some parts of their structure have greater electron density than others. This is again a result of differences in electronegativity. For example, chlorine is more electronegative than carbon. Consequently, bonds between Read more…
Ion-ion interactions Recall that ions are atoms or molecules that have lost or gained one or more electrons with respect to their electrically neutral counter-parts, such that they have a net electric charge. As a result, two or more ions can exert electrostatic forces on each other. This is the Read more…
Electrostatics Recall that electrostatics is the study of stationary electric charges. Charged particles are characterized as either positive or negative. Like charges repel, whereas opposite charges attract. Symmetries in the laws of electromagnetism imply that these roles could be reversed with minimal consequence to our theoretical understanding or its pertinence Read more…
Introduction Intermolecular interactions between adjacent atoms, molecules, and ions not chemically bonded to one another are mediated by a short list of intermolecular forces which are primarily electrostatic in nature. The importance of each of these forces for a given system depends on the properties of the atoms, ions, and/or Read more…
