Science, Tech, Math › Science Intermolecular Force Definition in Chemistry Share Flipboard Email Print Intermolecular forces are those that occur between molecules. ALFRED PASIEKA, Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated July 03, 2019 The intermolecular force is the sum of all the forces between two neighboring molecules. The forces result from the actions of the kinetic energy of atoms and the slight positive and negative electrical charges on different parts of a molecule that affect its neighbors and any solute that may be present. The three main categories of intermolecular forces are London dispersion forces, dipole-dipole interaction, and ion-dipole interaction. Hydrogen bonding is considered a form of dipole-dipole interaction, and so contributes to the net intermolecular force. In contrast, intramolecular force is the sum of the forces that act within a molecule between its atoms. The intermolecular force is measured indirectly using measurements of various properties, including volume, temperature, pressure, and viscosity.