Lanthanum, atomic no. 57, symbol La, weight at 138.91, is the first element in the rare earth or lanthanide series. It is the model for all the other trivalent rare earths. After cerium, it is the second most abundant of the rare earths.
Lanthanum-rich lanthanide compounds have been used extensively for cracking reactions in FCC catalysts, especially to manufacture high-octane gasoline from heavy crude oil.
Lanthanum-Rich Rare Earth metals play the important roles in hydrogen storage bettaries.
Lanthanide zirconates are used for their catalytic and conductivity properties and lanthanum stabilized zirconia has useful electronic and mechanical properties.