Term: Peierls transition
https://doi.org/10.1351/goldbook.P04468

Definition:
A metal-insulator transition in quasi one-dimensional solids that occurs as a result of a band gap opening up at the Fermi energy due to a displacive distortion of the regular array increasing the unit cell length, usually a dimerization; the decrease in electronic energy outweighs the increase in lattice energy. Example: The transition in methylethylmorpholinium tetracyanoquinodimethanide at 335 K.

Related Terms:
1) metal-insulator transition (http://doi.org/10.1351/goldbook.M03863).
2) fermi energy (http://doi.org/10.1351/goldbook.F02340).
3) unit cell (http://doi.org/10.1351/goldbook.U06562).
4) dimerization (http://doi.org/10.1351/goldbook.D01744).

Source: PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 588 (https://doi.org/10.1351/pac199466030577)

Citation: 'Peierls transition' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.P04468

License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.

Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.