Use
The lanthanoid series consists of 14 elements (cerium to lutetium) and they are also called f-block metals,
as the valence shell of lanthanoids contains 4f orbitals. Lanthanoids are named after the element lanthanum
(La), which itself is a d-block metal. Nevertheless, because of its very similar chemical behaviour, lanthanum
is often also classified as a lanthanoid. The term rare earth metals describes the lanthanoid series together
with lanthanum (La), scandium (Sc) and yttrium (Y).Mostly, lanthanoids are used in the production of batteries, lasers and other technological devices. Some
lanthanoids salts, such as the salts of lanthanum, cerium and gadolinium (highlighted in Figure 9.1), are
increasingly used in a clinical setting, for example, as a phosphate binder in the treatment of renal osteodystrophy
or as MRI (magnetic resonance imaging) contrast agents (CAs).