Polyatomic Ion: Definition and Examples

What Is a Polyatomic Ion in Chemistry?

polyatomic ion
This is the chemical structure of the pyrophosphate anion, an example of a polyatomic ion. Todd Helmenstine
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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.
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Updated on January 12, 2019

Polyatomic ion definition: A polyatomic ion is an ion composed of two or more atoms.

Examples: The hydroxide cation (OH-) and the phosphate cation (PO43-) are both polyatomic ions.

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Helmenstine, Anne Marie, Ph.D. "Polyatomic Ion: Definition and Examples." ThoughtCo, Aug. 25, 2020, thoughtco.com/definition-of-polyatomic-ion-and-examples-605534. Helmenstine, Anne Marie, Ph.D. (2020, August 25). Polyatomic Ion: Definition and Examples. Retrieved from https://www.thoughtco.com/definition-of-polyatomic-ion-and-examples-605534 Helmenstine, Anne Marie, Ph.D. "Polyatomic Ion: Definition and Examples." ThoughtCo. https://www.thoughtco.com/definition-of-polyatomic-ion-and-examples-605534 (accessed May 16, 2022).