| Amount | of | substance | used | .47535 | gr. |
| ” | ” | cadmium | found | .14980 | ” |
| Cadmium. | |||||
| 31.51 per cent. | |||||
As these results did not correspond to the composition represented by the formula Cd₄I₇, which our experience with the chloride and bromide had led us to expect, we reheated the material for several hours with an excess of the metal. Two analyses of the product gave:
showing that the iodide had taken up during the first heating all the metal which it could retain. The analytical results suggest the formula Cd₁₂I₂₃, in which the calculated percentages are:
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.