Piezoelectric single crystals (piezocrystals) of lead magnesium niobate-lead titante (PMN-PT) and lead zinc niobate-lead titanate (PZN-PT) have extremely large electromechanical coupling coefficients and exhibit strains of over one percent. The technical significance of these properties to devices is enormous and includes a doubling of bandwidth, decreased package size, and increased resolution. The exploitation of electroactive single crystals is currently being pursued for naval sonar and medical ultrasound transducers. To accelerate the maturation and implementation of piezocrystals from the research arena into commercial devices, an international working group completed an IEEE material standard in 2017: The Standard for Relaxor-Based Piezoelectric Single Crystal Materials for Transducer and Actuator Applications. The working group is now working on extensions to this standard including into ternary piezocrystal materials.