Abstract: It was found that the photosensitivity effect of a crown compoundon octahedal AgBremulsion is related to both the heteroatoms in the crown ether and the cavity size of it.1,7, 10,16-Tetraoxa-4,13-dithiacyclooctadecan(2S-18-C-6),which contains twosulfur atoms, improved the photosensitivity a great deal,while 1,7,10,16-tetraoxa-4,13-diazacyclooctadecan (2N-18-C-6),and 1,4,7,10,13, 16-hexaoxacyclooctadecan(18-C-6)had no effect on the emulsion. Although 7,8-benzo-1,5-dithiacyclononane(BDT),13,14-benzo-1,4,8,11-tetrathiacyclotetradecane(TTX)and1,4,8,11-tetrathiacyclotetradecane(TTP)contain sulfur atoms,they did not improve the pho-tosensitivitv for their cavity sizes are not corresponding to the diameter of Ag⁺.Never-theless,the sensitivity can be improved,while the fog is increased, in combining TTP or TTX with gold salt.The addition of a crown compound to the emulsion made the grainionic conductivity decreased.

Key words: crown ether, emulsion, sensitization, complexing