The term allotropy has also been applied to inorganic compounds, identical in composition, but assuming different crystallographic forms. Mercuric oxide, sulphide and iodide; arsenic trioxide; titanium dioxide and silicon dioxide may be cited as examples.
It may be recognized by the violet coloration it gives when added to a very dilute solution of potassium bichromate in the presence of hydrochloric acid; by the orange-red colour it gives with a solution of titanium dioxide in concentrated sulphuric acid; and by the precipitate of Prussian blue formed when it is added to a solution containing ferric chloride and potassium ferricyanide.
calcined clays generally provide the best brightness, titanium dioxide extension and dry hide.
Titanium Titanium metal made by electrolysis of titanium dioxide in molten calcium chloride.
The hi-tech paving slabs have a top layer containing titanium dioxide which helps to break down pollutant nitrogen dioxide gas from car fumes.