Chemical garden

A chemical garden is a sight experiment are given in the colored various heavy metal salts in an aqueous solution of sodium silicate.

The ions of the heavy metals react on the interface with poorly soluble, colored silicates. If one uses large crystals of salts of heavy metals to some bizarre formations arise with a fractal appearance. The shape results from the fact that the interface between the heavy metal salt, or its concentrated solution and the glass of water acts as a semipermeable membrane ( precipitate membrane) and can flow through osmosis water. Therefore, the membrane expands and bursts under certain circumstances. As the salt density is lowest at the top of the structure, it grows mainly upwards. But the ramifications to the sides also held, so that a plant-like structure results.

Salts which can be used are, for example

• Alum ( potassium aluminum sulfate ) - white
• Copper sulphate - blue
• Chromium ( III ) chloride - green
• Nickel sulfate - green
• Iron (II ) sulfate - green
• Iron (III ) chloride - orange brown
• Cobalt chloride - purple