<P> Commercially pure flat product (sheet, plate) can be formed readily, but processing must take into account the fact that the metal has a "memory" and tends to spring back . This is especially true of certain high - strength alloys . Titanium cannot be soldered without first pre-plating it in a metal that is solderable . The metal can be machined with the same equipment and the same processes as stainless steel . </P> <P> Titanium is used in steel as an alloying element (ferro - titanium) to reduce grain size and as a deoxidizer, and in stainless steel to reduce carbon content . Titanium is often alloyed with aluminium (to refine grain size), vanadium, copper (to harden), iron, manganese, molybdenum, and other metals . Titanium mill products (sheet, plate, bar, wire, forgings, castings) find application in industrial, aerospace, recreational, and emerging markets . Powdered titanium is used in pyrotechnics as a source of bright - burning particles . </P> <P> About 95% of all titanium ore is destined for refinement into titanium dioxide (Ti O 2), an intensely white permanent pigment used in paints, paper, toothpaste, and plastics . It is also used in cement, in gemstones, as an optical opacifier in paper, and a strengthening agent in graphite composite fishing rods and golf clubs . </P> <P> TiO 2 powder is chemically inert, resists fading in sunlight, and is very opaque: it imparts a pure and brilliant white color to the brown or gray chemicals that form the majority of household plastics . In nature, this compound is found in the minerals anatase, brookite, and rutile . Paint made with titanium dioxide does well in severe temperatures and marine environments . Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond . In addition to being a very important pigment, titanium dioxide is also used in sunscreens . </P>

What is the oxidation number of the titanium atom in tio 2