Synthesis and characterization of PbI2 polycrystals

Single-phase PbI2 polycrystalline material for single crystal growth was synthesized by two-temperature vapor-transporting method (TVM), directly from highly pure lead and iodine with excess lead without according to the PbI2 stoichiometry. It is found that there is an immiscible phenomenon of two melts in the synthesis experiment, and the melts solidified until cooled down to room temperature. X-ray diffraction (XRD) analysis and Energy dispersive X-ray (EDX) microanalysis indicate that the solidified materials are single-phase PbI2 polycrystal and nearly pure lead. Considering the observed immiscible phenomenon and the data given in paper [1], it is able to confirm that there is a new immiscible region L2+L3 in Pb-I phase diagram, which is very important to PbI2 polycrystal synthesis and single crystal growth. Using single-phase PbI2 polycrystalline material synthesized by our method, PbI2 single crystal with size of ?15mm×30mm was grown by vertical Bridgman method. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim