Science, Tech, Math › Science How to Define a Pi Bond in Chemistry Print JoJan / Wikimedia Commons / CCA-SA 3.0 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 03, 2019 A pi bond (π bond) is a covalent bond formed between two neighboring atom's unbonded p-orbitals. Read More What Is a Covalent Bond in Chemistry? By Anne Marie Helmenstine, Ph.D. An unbound p-orbital electron in one atom forms an electron pair with a neighboring atom's unbound, parallel p-orbital electron. This electron pair forms the pi bond. Double and triple bonds between atoms are usually made up of a single sigma bond and one or two pi bonds. Pi bonds are generally denoted by the Greek letter π, in reference to the p orbital. The symmetry of a pi bond is the same as that of the p orbital as viewed down the bond axis. Note d orbitals also form pi bonds. This behavior is the basis of metal-metal multiple bonding. Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "How to Define a Pi Bond in Chemistry." ThoughtCo, Apr. 5, 2023, thoughtco.com/definition-of-pi-bond-605519. Helmenstine, Anne Marie, Ph.D. (2023, April 5). How to Define a Pi Bond in Chemistry. Retrieved from https://www.thoughtco.com/definition-of-pi-bond-605519 Helmenstine, Anne Marie, Ph.D. "How to Define a Pi Bond in Chemistry." ThoughtCo. https://www.thoughtco.com/definition-of-pi-bond-605519 (accessed March 29, 2024). copy citation