Science, Tech, Math › Science Molecular Orbital Definition Print A molecular orbital is a mathematical function that describes an electron in a molecule. Adisonpk, 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. 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. Learn about our Editorial Process Updated on July 10, 2019 A molecular orbital is an orbital or wave function of a molecule's electron. The function may be used to calculate the probability of finding an electron within a specified space or to predict the molecule's chemical and physical properties. Robert Mulliken introduced the term "orbital" in 1932 to describe a one-electron orbital wave function. Electrons around a molecule can be associated with more than one atom and are often expressed as a combination of atomic orbitals. Atomic orbitals within a molecule can interact if they have compatible symmetries. The number of molecular orbitals is equal to the number of atomic orbitals combined to form a molecule. Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Molecular Orbital Definition." ThoughtCo, Aug. 29, 2020, thoughtco.com/definition-of-molecular-orbital-605367. Helmenstine, Anne Marie, Ph.D. (2020, August 29). Molecular Orbital Definition. Retrieved from https://www.thoughtco.com/definition-of-molecular-orbital-605367 Helmenstine, Anne Marie, Ph.D. "Molecular Orbital Definition." ThoughtCo. https://www.thoughtco.com/definition-of-molecular-orbital-605367 (accessed April 23, 2024). copy citation