Abstract: The molar enthalpy change, the molar entropy increase, the Gibbs free energy and the balance constant of PbI2 polycrystal synthesis reaction were calculated in this paper. Based on the thermodynamics analysis,the feasibility of controlling synthesis reaction temperature on 723K upon the melting point (678K) of PbI2 was discussed also. Through the craft controlling on 723K,highly pure and single phase PbI2 polycrystal was synthesized by two temperature vapor transporting method(TVM).The result of XRD analysis indicates the temperature controlling craft accordant with thermodynamics calculating which can be used for PbI2 pelycrystal synthesis effectively.

Key words: The molar enthalpy change, the molar entropy increase, the Gibbs free energy and the balance constant of PbI2 polycrystal synthesis reaction were calculated in this paper. Based on the thermodynamics analysis,the feasibility of controlling synthesis reaction temperature on 723K upon the melting point (678K) of PbI2 was discussed also. Through the craft controlling on 723K,highly pure and single phase PbI2 polycrystal was synthesized by two temperature vapor transporting method(TVM).The result of XRD analysis indicates the temperature controlling craft accordant with thermodynamics calculating which can be used for PbI2 pelycrystal synthesis effectively.