Gold(III) oxide

Brown powder

Fixed

3.6 g · cm -3

Decomposition at about 150 ° C in Au and O2

Insoluble in water

Attention

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Gold (III ) oxide ( Au2O3 ) is the most stable oxide of the chemical element known gold. It is a red-brown, crystalline, light -sensitive solid. The compound is thermally unstable and decomposes at about 160 ° C in the elements again. Au2O3 has a distorted square planar crystal structure consisting of AuO4 units.

Representation

The connection can be made due to the noble nature of elemental gold not by oxidation with oxygen. However, it is represented by the direct reaction of gold with an oxygen plasma. Chemically you go from stable in aqueous solution Trichlorogold hydrate AuCl3 · H2O (actually Hydrogentrichlorohydroxidoaurat (III ) H [ AuCl 3 (OH)] ), or Tetrachloridogoldsäure H [ AuCl4 ] · 4 H2O from which, mixed with sodium carbonate, as a brown precipitate Au2O3 · x H2O fails. After drying over silica gel, this water is split off and gives Au2O3 2-3 · H2O. This can then be further converted the four-week annealing at 280 ° C and 3000 bar pressure to pure polycrystalline and anhydrous gold (III ) oxide Au2O3.

Use

Gold oxide can be used to color glasses ( gold ruby ​​glass), special applications in optoelectronics are also possible.