Potassium fluotitanate, preparation

Titanium metal also can be produced by electrolytic methods. In electrolysis, fused mixtures of titanium tetrachloride or lower chlorides with alkaline earth metal chlorides are electrolyzed to produce metal. Also, pure titanium can be prepared from electrolysis of titanium dioxide in a fused bath of calcium-, magnesium- or alkali metal fluorides. Other alkali or alkaline metal salts can be substituted for halides in these fused baths. Other titanium com-pouds that have been employed successfully in electrolytic titanium production include sodium fluotitanate and potassium fluotitanate. 

Merthyr Tydvil, but F. Wohler (18) showed in 1849 that these were not the metal itself but a mixture of the nitride and cyanide. In 1825 Berzelius (20) prepared some very impure amorphous titanium by reducing potassium fluotitanate, K2TiF6, with potassium. Although the resulting black powder gave a metallic streak, it was insoluble in hydrofluoric acid and therefore could not have contained much titanium metal (23). 

In 1849 Wohler and H. Sainte-Claire Deville attempted to prepare pure titanium by Berzelius method, but used a closed crucible in order to exclude air. When they found that the product thus obtained still contained titanium nitride, they heated boats containing potassium and potassium fluotitanate in an atmosphere of hydrogen and obtained a gray powder which showed a metallic luster when examined with a microscope (7,10,18). Wohler and Deville thought they had the metal, but, in the opinion of W. M. Thornton, Jr. (23), they were still dealing with the nitride. 

Potassium fluotitanate, K2TiFe, is a convenient source for the preparation of other titanium salts. It can easily be obtained pure because it is sparingly soluble (0.6 gram in 100 grams of water at 0°), and it is therefore used as a primary standard in oxidation-reduction titrations. Its existence and stability illustrate the power of the fluoride ion to form stable C9mplex ions and to bring out the highest coordination number of an element. 

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See also in sourсe #XX -- [ ]

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