Lead iodide has number of applications and is considered to be a potential room temperature radiation detector. The phenomenon of polytypism in PbI2 is posing a problem. Even when the PbI2 crystals are stored for some time, there are structural changes in the crystals. It causes deterioration in functioning of devices. Considering a vast amount of data available on PbI2, a comparative study on the growth and storage of PbI2 crystals has been made and it has been concluded that impurities are responsible for the phase transformations. Further, it is suggested that the role played by vacancies can not be ignored.
