The local structure of a typical molten salt ZnCl2, in which the chemical bonds can be viewed as half ionic and half covalent, has been studied by molecular dynamics simulations. Comparing with the recent EXAFS experimental results in the radial distribution functions simulated from different different effective potentials, we found that KDR potential is a useful one and able to give a more realistic representation of ZnCl2 melt. Based on the instantaneous configurations given by the simulations with KDR potential, the near-neighbor structures in the crystalline and molten states of ZnCl2 have been studied by using the bond-order-parameter method. The results indicates that there exist the same stable Zn-Cl tetrahedral structures in molten ZnCl2 as in crystalline state while the square deviations of thermal fluctuation σ of Zn-Cl units are different from each other. The calculations show σ=5.0℃ in crystalline, 300K and σ=12.2℃ in molten, 613K. In addition, the network-like structures and the transprot properties of molten ZnCl2 were discussed in this paper.

Key words: CRYSTAL STRUCTURE, ZINC CHLORIDE, RADIAL DISTRIBUTION FUNCTION