Scandium group

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◄    Scandium    Group ►
group 3
period
4th 21
Sc
5 39
Y
6th 57
La
7th 89
Ac

The third group (scandium group) (III. Subgroup) in the periodic table of the elements includes the elements scandium (Sc), yttrium (Y), lanthanum (La) and actinium (Ac). Scandium and yttrium are classified as light metals . The elements following the lanthanum in the 6th period are called lanthanoids , those following actinium in the 7th period are called actinides .

Occurrence

The elements with a proportion of 5.1 · 10 −4 (Sc), 2.6 · 10 −3 (Y), 1.7 · 10 −3 (La) and 6.1 · 10 −14 are located in the earth's crust (Ac) weight percent before.

properties

  • The metals

  • Scandium

  • yttrium

  • Lanthanum

Physical Properties

Properties of the scandium group metals
Surname Scandium yttrium Lanthanum Actinium
Melting point 1814 K (1541 ° C) 1799 K (1526 ° C) 1193 K (920 ° C) 1323 K (1050 ° C)
boiling point 3103 K (2830 ° C) 3609 K (3336 ° C) 3743 K (3470 ° C) 3573 K (3300 ° C)
density 2.985 g cm −3 4.472 g cm −3 6.17 g cm −3 10.07 g cm −3
Appearance silvery white silvery white silvery white silvery
Atomic radius 160 pm 180 pm 195 pm 195 pm

Chemical properties

The chemical properties of the elements of the scandium group are more similar to the preceding main group metals of the 2nd group of the periodic table ( alkaline earth metals ) than the elements of the 13th group ( earth metals / III. Main group).

The elements of the 3rd group have in common that the outer d-shell is single, the outer s-orbital is double. That is why they are , with a few exceptions, in compounds in the +3 oxidation state.

Electrochemically , the elements of the scandium group are less noble than aluminum and nobler than the alkaline earth metals. The ignoble character increases with increasing atomic mass .

literature

  • Hermann Sicius: rare earth metals: lanthanoids and third subgroup . Springer Spectrum, Wiesbaden 2015, ISBN 978-3-658-09839-1 .