The Element Lanthanum
Atomic Number: 57
Atomic Weight: 138.90547
Melting Point: 1191 K (918°C or 1684°F)
Boiling Point: 3737 K (3464°C or 6267°F)
Density: 6.15 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 6
Group Number: none
Group Name: Lanthanide
What's in a name? From the Greek word lanthaneia, which means "to lie hidden."
Say what? Lanthanum is pronounced as LAN-the-nem.
History and Uses:
Lanthanum was discovered by Carl Gustaf Mosander, a Swedish chemist, in 1839. Mosander was searching for impurities he believed existed within samples of cerium. He treated cerium nitrate (Ce(NO3)3) with dilute nitric acid (HNO3) and found a new substance he named lanthana (La2O3). Roughly 0.0018% of the earth's crust is composed of lanthanum. Today, lanthanum is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements that can contain as much as 25% lanthanum.
Lanthanum is one of the rare earth elements used to make carbon arc lights which are used in the motion picture industry for studio lighting and projector lights. Lanthanum also makes up about 25% of Misch metal, a material that is used to make flints for lighters. Lanthana (La2O3) is used to make the glass used in camera lenses and in other special glasses.
Estimated Crustal Abundance: 3.9×101 milligrams per kilogram
Estimated Oceanic Abundance: 3.4×10-6 milligrams per liter
Number of Stable Isotopes: 1 (View all isotope data)
Ionization Energy: 5.577 eV
Oxidation States: +3
3s2 3p6 3d10
4s2 4p6 4d10
5s2 5p6 5d1