Rare-earth carbonate is acid-leached, and the individual REEs are peeled off by solvent extraction (typically bis-2-ethylhexyl phosphoric acid, HDEHP); La2O3 is reduced to metal by Ca or by molten-salt electrolysis.
Research Elements La · atomic number 57 Lanthanide · period 6 [Xe] 5d1 6s2 Shells: 2, 8, 18, 18, 9, 2 Valence electrons: 2 in the outer shell (6s2), and 1 in 5d1 Green dots are the outer shell's s and p electrons. Softer green dots are the d electrons of transition metals, and the d and f electrons of lanthanides and actinides: they often take part in bonding, but not always. Grey dots are the core. Ground-state configuration from the NIST Atomic Spectra Database (A. Kramida, Yu. Ralchenko, J. Reader and the NIST ASD Team). Abundance is the mole fraction of the element found as that isotope on Earth; digits in parentheses are the uncertainty in the last digits. Masses and abundances from NIST, Atomic Weights and Isotopic Compositions (J. S. Coursey, D. J. Schwab, J. J. Tsai and R. A. Dragoset, National Institute of Standards and Technology).Lanthanum
Electrons
How it's obtained
Natural isotopes
Isotope Relative atomic mass Abundance 138La 137.9071149(37) 0.0008881(71) 139La 138.9063563(24) 0.9991119(71)