Elements from the lanthanide series are used for petroleum production, lasers, magnets, projectors, X-ray screens and as a component of steel and magnesium alloys. The lanthanides are soft, highly reactive metals that burn easily and act as strong reducing agents.
Lasers are the most prevalent industrial use of lanthanide elements. Another important use of these elements is magnetic technology; samarium and neodymium compounds are used in powerful magnets. These magnets form essential components of radar and propulsion systems in military applications. Rare earth magnets are also used in hybrid cars and as educational toys.
There are 15 elements in the lanthanide group: lanthanum, cerium, praseodymium, neodymium, prometheum, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. The group draws its name from lanthanum, the first element in the group.
The lanthanide series elements are collectively known as the rare earth elements, a group that also includes the transition metals yttrium and scandium. These are named for their perceived rarity, though all the lanthanides are more common than platinum group metals. All the lanthanides except for promethium are natural elements; promethium exists only as a product of radioactive decay. Uranium and plutonium are both capable of decaying into promethium.