https://doi.org/10.1351/goldbook.P04468
A @[email protected] in quasi one-dimensional solids that occurs as a result of a band gap opening up at the @[email protected] due to a displacive distortion of the regular array increasing the @[email protected] length, usually a @[email protected]; the decrease in electronic energy outweighs the increase in lattice energy. Example: The transition in methylethylmorpholinium tetracyanoquinodimethanide at \(335\ \text{K}\).