Glass is Green

This section is about an age-old material, glass, which will undoubtedly be the building material of the future - and for several reasons. The transparency of glass makes it the ideal medium for solar cells, and embedding these in a window would seem a logical step to take and such material is now being manufactured. 

138 Better Living (III) Minor Metals for Major Advances 

The trouble with glass is that it seems to attract dirt, and as we know from our own homes it has to be cleaned, especially in urban environments where city dust and vehicle fumes can settle as a thin film. 

A new kind of self-cleaning window was launched by Henkel in 2004 and it made use of silica nanoparticles which align themselves on the glass to form an invisible film with a negative charge which also makes the glass attractive to water, in this case to the hydrogen atoms of water molecules, but the result is the same the surface is covered with a film of water and not droplets. 

Glass may be the cladding material of the future, thanks in no small part to titanium, but this element may well have an enchanting future in store. 

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One way to tell whether a glass plate is made of pure silica or soda-lime silica glass is to view it on edge. The silica plate is clear, whereas the window glass is green. Explain. 

These materials are normally colored by low concentrations of 3d transition-metal ions or more rarely by lanthanide ions. The pale green color of ordinary window glass is due to the presence of Fe2+ impurities and small amounts of doping of Cr3+ into AI2O3 (corundum) creates ruby. 

Commercially soft glass is used in items such as window panes, bottles, jars, and drinking glasses. Soft glasses can take colors readily (as brown and green bottles show and as do the many hues and colors that are created by artisans such as the Italian glass masters). ... 

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