The scandium is a chemical element, of symbol Sc and Atomic number 21.

It is a soft Métal of transition, of silver plated white aspect. One finds scandium in some rare minerals coming from Scandinavia. It is classified with the Radium, the Yttrium and the Lanthanide S in the Rare earths.

Notable characteristics

Scandium is an element metal soft, rare, trivalent, very light which becomes yellowish or pink when it is exposed to the air. This element resembles more chemically yttrium and rare earths that it does not resemble the aluminum and the titanium which are its neighbors in the periodic table. The state of the most common oxidation of scandium is +3.

Applications

The worldwide production is weak, about 4 tons and its high price (10 000$ the kilo).
By adding scandium iodide in a lamp to metal halide, one obtains a source of light spectralement comparable with the sun (Température of color of 4000°K - “white neutral”) which is used as source of light for the video of night or in intérieur.
It is radioactive but much more slightly than radium. The radioactive isotope ⁴⁶Sc, because of its short Half-life (4 hours), is used as marker in the refineries of Pétrole at the time of the Craquage and for the leak detection of canalisations.
Scandium having a melting point much higher than that of aluminum and almost so light (density 2,9) is studied for possible aerospace applications.

The USSR largely developed the industrial production of scandium and optimized an aluminum alloy comprising scandium 2%, which reinforces considerably the mechanical characteristics of aluminum. This alloy is usually used in the Russian military aeronautical construction industries. A property complementary to this alloy is that it is weldable whereas it is not the case of an alloy aluminum lithium developed in Occident at the same time (this problem is solved today) for equivalent mechanical characteristics.

The scandium most powerful of anti recristallizing is known, in aluminum. This property which currently interests the aircraft industry. One uses it atvery low rates (lower than 0,5%) for, for example, to preserve a texture fibrée even after multiple heat treatments.

History

Scandium (Latin: scandia→scandinavie) was discovered by Lars Fredrick Nilson in 1879 when him and its team sought rare earths. Nilson highlighted the new element by spectral analysis made starting from ore of Euxénite and Gadolinite. In order to insulate the element it treated 10 kilograms of euxenite in order to obtain 2 grams of scandium oxide (Sc₂O₃) very pure.

In 1869 Dmitri Mendeleïev predicts certain properties of scandium that it named ekaboron then, by using its periodic law. Per Theodor Cleve discovered scandium oxide about at the same time but contrary to Nilson, Cleve determined that scandium was identical to the ekaboron.

In 1937, for the first time of metal scandium is produced by electrolysis of a mixture of Potassium, Lithium, and scandium oxide melted with 700-800°C. The first pure metal scandium book with 99% was not produced before 1960.

Occurrence

The only known sources of concentrated scandium are the ores of Thortveitite, Euxénite and Gadolinite which one finds in small quantity in Scandinavia. One does not find naturally scandium metal. Scandium is the 23e the most abundant element in the Sun, but only the 50e on ground. One finds it distributed in a uniform way on ground in more than 800 minerals. It represents most of a rare ore, thortveitite, and one also finds it like residue after the extraction of the Tungstène of the Wolframite.

Scandium is currently mainly a by-product of the purification of the Uranium. One industrially isolates it by reduction from fluoride from scandium in the presence of metal Calcium.

Isotopes

One finds naturally one isotope of scandium the ⁴⁵Sc. One discovered 13 other isotopes of which most stable are the ⁴⁶Sc with a 83,79 days half-life, the ⁴⁷ with a 3,3492 days half-life, and the ⁴⁸Sc of a 43,67 hours half-life. The other isotopes have a whole a half-life lower than 4 hours and the greatest lower part at 2 minutes. The isotopes of scandium have an atomic weight varying from 39,978 uma for the ⁴⁰Sc, up to 53,963 uma for the ⁵⁴Sc. The primary mode of disintegration for the isotopes before ⁴⁵Sc is the orbital electron capture whereas after it is the emission béta.

Precautions/toxicology

The metal scandium powder is flammable.

Simple: Scandium

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