Environmentally Friendly Ferroelectrics Ferroelectrics—which are widely used as piezo elements, sensors, and actuators—maintain charge polarization even in the absence of an external electric field. The best ferroelectric properties are found in perovskites such as barium titanate (BTO) and lead zirconate titanate; however, environmentally friendly, lead-free alternatives are highly desirable. Fu et al. (p. 425 ; see the Perspective by Bonnell ) find that the organic molecular crystal diisopropylammonium bromide has ferroelectric properties comparable to those of BTO and may represent a viable alternative to perovskites.