Gallium complex composition, process for doping silver halide emulsion grains with gallium complex composition, and gallium-doped silver halide emulsion

This invention relates to gallium complex compositions which may be used in doping silver halide emulsions for use in silver halide photography. More specifically, the invention relates to new gallium halide complexes, a method for preparing silver halide emulsions incorporating gallium dopant, and to photographic elements which contain one or more of such emulsions. A gallium halide coordination complex is described of the formula (I):wherein R represents a lower alkyl group of from 1-3 carbon atoms; X is Cl, Br, or I; and x is from 1-3, y is from 1-3, and x+y=4. In a further aspect, a process for incorporating gallium in a silver halide emulsion is described comprising precipitating silver halide emulsion grains in a reaction vessel, wherein a gallium halide coordination complex of the formula (I) is introduced into the reaction vessel or formed in situ during precipitation of the silver halide grains. The isolation, or in-situ preparation, of a six coordinate gallium halide complex of Formula (I) in accordance with the invention has been found to enable the preparation of gallium doped silver halide emulsions with improved speed/grain performance.