Cadmium. Iodine. 31.53 per cent. 68.47 per cent. In its conduct towards dilute hydrochloric and acetic acids and water the substance behaves like the corresponding chloride and bromide. The Preparation of Cadmous Hydroxide and Oxide. When the substance Cd₄I₇ is treated with water a complicated reaction takes place. The general character of the reaction appears to be the same with the chloride, bromide and iodide. The decomposition of the chloride was studied more thoroughly than that of the other compounds. When the finely powdered chloride is treated with water it yields cadmic chloride which passes into solution, a small quantity of a white flocculent material which may be cadmic hydroxide but which in no case could be entirely freed from traces of chlorine, and a highly lustrous crystalline substance which rapidly lost its crystalline appearance and passed over into a grayish white amorphous compound, which when freed from chlorine was found to be cadmous hydroxide, of the formula Cd(OH). The separate products resulting from the treatment with water were analyzed. First Analysis: Amount of Cd₄Cl₇ treated with water 1.45970 gr. Cadmium found in flocculent precipitate .02318 ” ” ” ” crystalline substance .09614 ” ” ” ” solution in water .81970 ” Total cadmium found .93902 ” Chlorine found in crystalline compound .00371 gr. ” ” ” solution in water .51671 ” Total chlorine found .52042 ” Approximately seven-eighths of the total cadmium dissolved as cadmic chloride while the remainder was contained in the flocculent precipitate and in the gray crystalline compound. Second Analysis: Amount of Cd₄Cl₇ treated with water 1.0794 gr. Cadmium found in flocculent precipitate .01469 ” ” ” ” solution in water .60795 ” Chlorine found in solution in water .38491 ” The percentage of cadmium in the white precipitate is less in this analysis than in the former. The cadmium in solution is again about seven-eighths of the total and the chlorine present in the same solution shows that the cadmium was all combined as cadmic chloride. All attempts to determine the composition of the gray crystalline compound failed, owing to the rapidity with which it decomposed with water. Even with the most rapid work it could not be isolated in the undecomposed condition. Analyses of the partially decomposed crystals gave variable proportions of metal and halogen but never less than eight equivalents of the former to one of the latter.