Ammonium Chlor-platinate, (NH4)2PtCl6, is closely similar in appearance to the potassium salt, with which it is isomorphous. It crystallises in regular octahedra.
The solubility of ammonium chlor-platinate in water at various temperatures is as follows:
| Temperature ° C. | 15.5 | 100 | | Grams (NH4)2PtCl6 per 100 grams H2O | 0.666 | 1.25 |
When heated, ammonium chlor-platinate decomposes in accordance with the equation:
3(NH4)2PtCl6 = 3Pt + 16HCl + 2NH4Cl + 2N2,
the metal being left behind as a dull grey, soft and porous mass known as spongy platinum or platinum sponge. The density of the salt is 3.034. |