Compounds
Lanthanum is not in many compounds; however, the compounds that do include lanthanum are used mostly for scientific purposes, although there are a few that have general uses. The two most common compounds that include lanthanum are lanthanum chloride and lanthanum oxide - also called lanthana.
Lanthanum chloride is a combination of the elements lanthanum and chlorine. This compound is used for both scientific and commercial purposes. A scientific use of this compound is as a Lewis acid. A Lewis acid (A) is a chemical compound that receives a pair of electrons from a Lewis base(B). The Lewis Base acts as an "electron-pair donor", and these two compounds together form something called an adduct (AB). This particular compound is a mild Lewis acid and it is used to help out chemical reactions that need acidic conditions in order to be completed. A commercial use for this compound is as a preventer of algae in swimming pools. It does this by by removing the phosphates in the pools that cause algae to grow.
Lanthanum oxide is another compound that is a combination of the elements lanthanum and oxygen. A commercial use of this compound is as a component in camera lenses and other special optical glasses. Lanthanum is capable of decreasing the hardness and density of other metals, and because of this, it can protect glasses and lenses of cameras from attack by alkali. Lanthanum oxide is also sometimes used in X-Ray machines, in the imaging intensifying screens.
