Glossary
Rare earths

Lanthanides (Ln); lanthanides (Ln)

A group of elements with very similar chemical properties and atomic numbers ranging from 57 to 71: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

Terres rares; rare earths (RE)

All the lanthanides and yttrium. Some authors also include scandium.

Light Rare Earths (LRE)

The elements lanthanum, cerium, praseodymium, neodymium and samarium.

Heavy Rare Earths (HRE)

The elements europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, to which yttrium is added.

Mischmetal; mischmetal

Alloys of...