Praseodymium metal is a soft, silvery, ductile and malleable element present in the periodic table with atomic number 59 and symbol Pr. It was first discovered by a German chemist named Carl F. Auer von Welsbach, in 1885. This element was separated from the neodymium, from another material called as didymium. Today, the metal praseodymium is mainly obtained from the process of ion exchange through monazite sand, which is a precious earth element.
Physical Properties of Praseodymium
- It is the third member of the lanthanide series. It is a ductile metal with a hardness comparable to that of silver.
- Itis the first of the lanthanides to have an electron configuration conforming to the Aufbau principle, which predicts the 4f orbitals to have a lower energy level than the 5d orbitals; this does not hold for lanthanum and cerium, because the sudden contraction of the 4f orbitals does not happen until after lanthanum, and is not strong enough at cerium to avoid occupying the 5d subshell.
- Solid praseodymium takes on the [Xe]4f25d16s2 configuration, with one electron in the 5d subshell like all the other trivalent lanthanides (all but europium and ytterbium, which are divalent in the metallic state).
- The element tends to form a black coating in the presence of air. Like other metals, Praseodymium does not get oxidized or does not possess the corrosion resistant feature.
- In the reaction with water, the metal forms praseodymium hydroxide giving out hydrogen gas. The metal usually exists in its trivalent state, Pr3+, in the compound form. The salts of this substance appear as pale green color.