Scandium

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Scandium
44.955910(8) 2
8
9
2
  Sc
21
1s22s22p63s23p63d14s2 3,4,d
[ ? ] Transition metal:
Properties:
Silvery-white, relatively soft metal.
Hazard:
Scandium dust is flammable and a fire hazard. It is not known to be toxic.


Scandium is a chemical element, having the chemical symbol Sc. Its atomic number (the number of protons) is 21 and its standard atomic weight is 44.9559 g•mol −1. It is found naturally as the principal component of the mineral thortveitite and in smaller quantities in more than 800 other minerals.[1]

Scandium is considered to be a member of the "transition metal" class of element. At a pressure of 101.325 kPa, it has a boiling point of 2836 °C, and a melting point of 1541 °C.

History

Lars Frederick Nilson reported the discovery of scandium in 1879.[2] Nilson was able to isolate about two grams of scandium oxide (Sc2O3) from the minerals euxenite and gadolinate. Nilson explains his choice of name as follows:[3]

For the element thus characterized I propose the name "scandium," which will bring to mind its presence in gadolinite or euxenite, minerals that have so far been found only in the Scandinavian Peninsula.

Nilson's subsequent work, assisted by his colleague at the University of Upsala, Per Theodor Cleve, correctly identified the molecular mass of the isolated oxide and the atomic number of the new element.[2] Nilson reported that scandium was equivalent to the hypothetical element ekaboron, proposed by Mendeleev while constructing the periodic table.

Pure metallic scandium was first isolated from a eutectic melt of lithium, potassium, and scandium chlorides in 1937 by Fischer, Brunger, and Greineisen[4] High purity scandium (99%) was first prepared in 1960.

Properties of scandium

Metallic scandium presents as a soft, silvery-white metal similar in appearance and consistency to yttrium. The most abundant isotope of scandium is scandium-45, present in nearly 100% abundance. Twelve additional radioactive isotopes have been identified.

References

  1. Lide, David R. (ed) CRC Handbook of Chemistry and Physics 75th ed., CRC Press: Ann Arbor, MI (1995).
  2. 2.0 2.1 Nilson, Lars Frederick Comptes Rendus, 88, 643-647 (1879). Excerpts available online here
  3. Nilson, Lars Frederick Comptes Rendus, 91, 118 (1880)
  4. W. Fischer, K. Brunger, and H. Greineisen. Z. Anore. Alleem. Chem. 231, 54 (1937).