Titanium

Chemical element, Ti, atomic number 22 and atomic weight 47.90. Its chemical behavior shows many similarities with that or silica and zirconium, as an element belonging to the first transition group. Its chemistry in aqueous solution, especially in the lower oxidation states, has some similarities with that of chrome and vanadium. Titanium is a transition metal light with a white-silvery-metallic colour. It is stong, lustrous, corrosion-resistant. Pure titanium is not soluble in water but is soluble in concentrated acids. This metal forms a passive but protective oxide coating (leading to corrosion-resistance) when exposed to elevated temperatures in air but at room temperatures it resists tarnishing.

The main oxidation state is 4+, although the states 3+ and 2+ are also known, but are less stable. This element burns in the air when it’s heated up to obtain the dioxide, TiO₂, and when it is combined with halogens. It reduces the water vapor to form the dioxide and hydrogen, and it reacts in a similar way with hot concentrated acids, although it forms trichloride with chlorhydric acid. The metal absorbs hydrogen to give TiH₂, and forms the nitride, TiN, and the carbide, TiC. Other known compounds are the sulfur TiS₂, as well as the lowest oxides, Ti₂O₃ and TiO, and the sulfurs Ti₂S₃ and TiS. Salts are known in the three oxidation states.

Applications

The titanium dioxide is extensively used as a white pigment in outside paintings for being chemically inert, for its great coating power, its opacity to UV light damage and its autocleaning capacity. The dioxide was also used once as a bleaching and opicifying agent in porcelain enamels, giving them a final touch of great brightness, hardness and acid resistance. A typical lipstick contais 10% titanium.

Titaium alloys are characterized by very high tensile strength even at high temperatures, light weight, high corrosion resistance, and ability to withstand extreme temperatures. ue to these properties they are principally used in aircraft, pipes for power plants, armour plating, naval ships, spacecraft and missiles. Titanium is as strong as steel but 45% lighter.

In medicine titanium is used to make hip and knee replacements, pace-makers, bone-plates and screws and cranial plates for skull fractures. It has also been used to attach false theet.