Element Chromium, Cr, Transition Metal. Chromium is closely related to manganese in the number of the series of compounds which it forms. Whereas, however, in the case of manganese, the acids corresponding to the higher stages of oxidation were somewhat unstable, these belong in the case of chromium to the most important and best-known compounds. Salts of the divalent dichromion, Cr. Salts of the trivalent trichromion, Cr.

Element Molybdenum, Mo, Transition Metal. Comes from the Greek molybdos. Meaning lead and the mineral lead glance. This was confused with molybdenite. All three minerals were previously known as molybdaena. In 1758, Cronstedt presumed that molybdenite. Are different minerals; 20 years late Scheele proved it obtaining Mo. Which he called Wasserbleyerde or molybdenum acid. Is a typical rare element with crustal abundance 1. The main commercial mineral, forming hydrothermal deposits; H.

Element Tantalum, Ta, Transition Metal. The discovery of transition metal tantalum. Symbolizing oxide is insoluble in acid, and was unable, just as the mythological Tantalos. Ekeberg called the ores in which tantalum. Was discovered tantalite and yttrotantalite. Perhaps Ekeberg isolated impure tantalum. Deep layers and upper mantle are poor by tantalum.

Element Titanium, Ti, Transition Metal. Titanium occurs in the crust of the earth in the form of its dioxide, Ti. Which, like silica, is either in the free state or combined with metallic oxides, forming titanates. Impure titanium dioxide is found in three distinct crystalline forms as rutile, brookite, and anatase; ilmenite or titanic iron ore is Fe. Titanite or sphene, Ca. Igneous rocks contain an average of 0. 74 per cent, of Ti.

Element Tungsten, W, Transition Metal. Was produced by de Elhuyar brothers, students of Bergman in 1783. They named the new metal wolfram. After the mineral wolframite in which tungsten. Miners of 1416 centuries noticed that roasting of the ore tales the tin away, transferring it into slag.

Element Zirconium, Zr, Transition Metal. Containing mineral hyacinth or a jargon from Sri Lanka, originally known as Ceylon has been known from deepest ages for its beautiful colors, from yellow-golden, brownish, to fumous-green. Hyacinth was considered to be a sort of topaz or ruby, with similar chemical compound, a gemstone now known as zircon. These minerals were not known to contain this element until Klaproth, in 1789, analyzed jargon. Was first prepared in 1914.

Element Hafnium, Hf, Transition Metal. In 1911 Urbain noticed several new lines in spectrum of the fractions of yttria mother solution and, thinking he had found a new element similar to the rare earths, called it celtium.