2. Titanium dioxide (TiO2)

2.1 Origin

Titanium (chemical symbol: Ti) is the fourth most abundant metal on Earth (after aluminum, iron and magnesium) and the ninth most abundant chemical element. Titanium accounts for 0.63% of the earth's crust by mass. It was discovered in England in 1791 by mineralogist William Gregor, who discovered the presence of a new chemical element in an ore called ilmenite. The element was rediscovered several years later by a German chemist, Heinrich Klaporth, in another ore, rutile. He gave this new chemical element the name titanium, in reference to the Titans (giant primordial deities who preceded the Olympian gods in Greek mythology), who were...