What are lanthanides

What are the lanthanides and lanthanides actually?

As an element group of the Lanthanoids denotes the 14 elements of the atomic numbers 58-71 following the lanthanum in the periodic table:
Cer (Ce), Praseodymium (Pr), Neodymium (Nd), Promethium (Pm), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb) and Lutetium (Lu).

The term "Lanthanoid" means "similar to lanthanum" and is derived from the fact that all elements of this group have chemical properties comparable to those of lanthanum.
In many US publications the designation Lanthanides (lanthanides) used for the elements lanthanum to lutetium, although -id generally denotes a negative ion (see chloride, sulfide, etc.).
Ln is used as a symbol for the lanthanides in the formula notation.

Furthermore, in the literature for these elements are the designations Rare earth metals (rare earth metals) or Rare earth (rare earths) in use, where the term "earth" originally referred to the metal oxides.
In addition to lanthanum and the lanthanides, yttrium and (more rarely) scandium are also counted among the rare earth metals.
The designation Rare earth metals is not really true, as the lanthanides are not really rare elements. So is z. B. cerium, the most common lanthanide, is as common as copper and nickel and also the rarest lanthanides (with the exception of promethium, which does not occur naturally) are more common than silver, gold and platinum.

In fact, the lanthanoids occur in minerals finely distributed and mixed with one another, so that for a long time it was difficult to separate a lanthanoid mixture due to their similar ionic radii and chemical properties.
Furthermore, one subdivides the rare earth metals according to their occurrence in nature.
The so-called Cerite earth contain the lanthanum and the lighter lanthanides (atomic numbers 58-63, cerium to europium), the Ytter earths the yttrium and the heavier lanthanoids (atomic numbers 64-71, gadolinium to lutetium).
Although lanthanum and yttrium do not actually belong to the group of lanthanides, they will be mentioned on the following pages due to their close chemical relationship.

Further texts on the subject of lanthanides

This page is part of a large website offering with further texts and experimentation instructions on Prof. Blume's educational server for chemistry.
Last revision: February 13, 2012, Dagmar Wiechoczek