Showing papers on "Selenourea published in 1969"

Metal complexes involving the heavier donor atoms. Part III. Stability of complexes of urea, semicarbazide, and their sulphur and selenium analogues with zinc, cadmium, and mercuric ions and the heats of formation of the mercuric complexes

Abstract: The basicity constants and heats of protonation of the ligands selenourea, semicarbazide, thiosemicarbazide, and selenosemicarbazide have been determined. The stability constants of complexes of urea, semicarbazide, and their sulphur and selenium analogues with zinc, cadmium, and mercuric ions have been measured by the metal electrode method and the heats of formation of the mercuric complexes by calorimetry. The relative donor properties of oxygen, sulphur, and selenium are compared.

Silver halide emulsions sensitized with a combination of sulfur and selenium for color photography

Abstract: CHEMICAL SENSITIZATION OF A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING A COLOR-FORMING COUPLER WITH A COMBINATION OF LABILE SULFUR WITH LABILE SELENIUM PROVIDES A SYNERGISTIC INCREASE IN SPEED. A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING A COLOR-FORMING COUPLER AND SENSITIZED WITH A COMBINATION OF A SULFUR SENSITIZER, SUCH AS SODIUM THIOSULFATE, WITH A SELENIUM SENSITIZER, SUCH AS DIMETHYL SELENOUREA, PROVIDES A SYNERGISTIC INCREASE IN SPEED AND OTHER DESIRED SENSITOMETRIC PROPERTIES.

Selenourea oxidation products: the structure of αα′-diselenobisformamidinium cation

Abstract: Aqueous solutions of silver(I) chloride–selenourea complexes decompose giving α,α′-diselenobisformamidinium dichloride.

Bleach-fix processing

Abstract: This application describes a bleach-fix process which comprises bleach-fixing photographic silver halide color material, after development of the silver image, in the presence of a watersoluble selenocyanate salt, selenourea, substituted selenourea or substituted selenouracil.