Amorphous Definition in Physics and Chemistry

Understand What Amorphous Means in Science

Unlike a crystalline solid, an amorphous solid lacks ordered internal structure.
Unlike a crystalline solid, an amorphous solid lacks ordered internal structure. Mina De La O / Getty Images
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.
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Updated on September 04, 2019

In physics and chemistry, amorphous is a term used to describe a solid which does not exhibit crystalline structure. While there may be local ordering of the atoms or molecules in an amorphous solid, no long-term ordering is present. In older texts, the words "glass" and "glassy" were synonymous with amorphous. However, now glass is considered to be one type of amorphous solid.

Examples

Examples of amorphous solids include window glass, polystyrene, and carbon black. Many polymers, gels, and thin films exhibit amorphous structure. Ice can take a crystal form as a snowflake or can form an amorphous solid.

Sources

  • Mavračić, Juraj; Mocanu, Felix C.; Deringer, Volker L.; Csányi, Gábor; Elliott, Stephen R. (2018). "Similarity Between Amorphous and Crystalline Phases: The Case of TiO₂." J. Phys. Chem. Lett. 9 (11): 2985–2990. doi:10.1021/acs.jpclett.8b01067
  • Zallen, R. (1969). The Physics of Amorphous Solids. Wiley Interscience.
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Helmenstine, Anne Marie, Ph.D. "Amorphous Definition in Physics and Chemistry." ThoughtCo, Aug. 27, 2020, thoughtco.com/definition-of-amorphous-604365. Helmenstine, Anne Marie, Ph.D. (2020, August 27). Amorphous Definition in Physics and Chemistry. Retrieved from https://www.thoughtco.com/definition-of-amorphous-604365 Helmenstine, Anne Marie, Ph.D. "Amorphous Definition in Physics and Chemistry." ThoughtCo. https://www.thoughtco.com/definition-of-amorphous-604365 (accessed April 19, 2024).