三酸化二金

化学的特性

Brownish-black powder, decomposed by heat.Keep in dark bottle. Soluble in hydrochloric acid; insoluble in water.

使用

Gold plating

純化方法

The most probable impurities are SO4and Cl-ions. Dissolve it in strong boiling KOH solution (ca 5M) and precipitate (care) with excess of 3N H2SO4. Then shake and centrifuge, resuspend in H2O and repeat the washing several times until free from SO4 and Cl ions. This gives a wet oxide which is dried in air, but decomposes to free gold in sunlight. It is advisable to keep it wet as it decomposes on drying (analyse wet sample). Store it away from light in the presence of H2O vapour. It evolves O2 at 110o. It is insoluble in H2O but soluble in HCl and conc HNO3. [Roseveare & Buehrer J Am Chem Soc 49 1221 1927.]