Discovered | Characteristics | Prepared | Uses

Gadolinium is a member of the lanthanide series of elements, which stretches from lanthanum (La) through lutetium (Lu).

As with other lanthanides, Marignac and Lecoq de Boisbaudran were involved in the discovery of Gd. Marignac thought that the widely studied rare earth didymia was a mixture of elements rather than an oxide of a single metal, but he was unable to find a new element. However, de Boisbaudran was able to isolate element 64 from didymia in 1879 using some of de Marignac's ideas.

It is a soft, ductile metal with a silvery appearance. In the solid state, the metal has a hexagonal closest packed structure.

The metal is obtained by reducing a halide with an "active" metal such as Ca or Li.

3 Li(s) + GdCl3(s) Gd(s) + 3 LiCl(s)

The reaction is carried out in a tantalum crucible at high temperature in a helium atmosphere (the latter being used to prevent oxidation of the metal).

In spite of its low abundance in the earth's crust, the element is used in making steel alloys and in the manufacture of electrical components. In addition, a garnet made of gadolinium and gallium is used for "bubble memories" in computers. And finally, since Gd is perhaps the best of the naturally occurring elements in absorbing neutrons, it is used in the control rods in nuclear reactors.