# Piezoelectricity

### From Online Dictionary of Crystallography

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Piezoélectricité (*Fr*). Piezoelectrizität (*Ge*). Piezoelectricidad (*Sp*).

## Definition

Piezoelectricity is the property presented by certain materials that exhibit an electric polarization when submitted to an applied mechanical stress such as a uniaxial compression. Conversely, their shape changes when they are submitted to an external electric field; this is the inverse piezoelectric effect. The piezoelectric effect and the inverse efect are described by third-rank tensors.

## Piezoelectric point groups

The appearance of piezelectricity is compatible with the symmetry properties of the non-centrosymmetric point groups, with the exception of 432. The 20 piezoelectric point groups are therefore:

1, 2, *m*, 222, 2*mm*,

3, 32, 3*m*, 4, [math]{\bar 4}[/math],422, 4*mm*, [math]{\bar 4}[/math]2*m*, 6, [math]{\bar 6}[/math],622, 6*mm*, [math]{\bar 6}[/math]2*m*

23, [math]{\bar 4}[/math]3*m*

## History

It is considerations of symmetry that led the brothers Jacques (1855-1941) and Pierre Curie (1859-1906) to the discovery of piezoelectricity on materials such as tourmaline, quartz, boracite, sodium chlorate, Rochelle salt (Curie J. and Curie P., 1880, *C. R. Acad. Sci. Paris*, **91**, 294-295, *Développement, par pression, de l'électricité polaire dans les cristaux hémièdres à faces inclinées*. The inverse piezoelectric effect was predicted by Lippmann G., 1881, *Ann. Chim. Phy.* **24**, 145-178, *Principe de conservation de l'électricité* and discovered by Curie J. and P., 1881, *C. R. Acad. Sci. Paris*, **93**, 1137-1140 , *Contractions et dilatations produites par*
des tensions électriques dans les cristaux hémièdres à faces inclinées*.*

## See also

Section 10.2 of *International Tables of Crystallography, Volume A*

Section 1.1.4 of *International Tables of Crystallography, Volume D*