Abstract: A series of unepitaxial and epitaxial multistructure tabular silver halide microcrystals with the same content but different distribution of iodide ions were prepared by double-jet precipitation. The ditribution of iodide ions and the position of epitaxial AgCl in the micro-areas of a single microcrystal were analysed by the means of Scanning Transmissive Electron Microscope(STEM)and X-ray Energy Dispersive Spectrorneter(EDS).It was found that the iodide and chlorine ions are distributed in the different microareas of tabular microcrystals as designed.The photophysical and photographic properties were investigatd,The results showed that the influence of epitaxial AgCl on the property of tabular silver halide microcrystals apparently depends on the multistructure of original tabular iedobromide micrcocrystals. Reasonable structure with high utilizing efficiency of photoelectrons as well as with high original sensitivity has few contribution to enhancing its sensitivity after being epitaxized.On the other hand,there will cause two results after epitaxizing on the emulsion with unreasonable structure:increasing the efficiency of formation of latent image and increasing the dispersion of latent image.

Key words: multistructure tabular silver halide microcrystal, Dember effect, epitaxial emulsion