Praseodymium
= Praseodymium
{wiki}
A <chemical element> of <atomic number> 59. Its trivalent <ion> has a $4f^2$ open-shell <electron configuration>. In <LS coupling>, <Hund's rules> select $L=5$, $S=1$, $J=4$, the ${}^3H_4$ <term symbol>. The corresponding free-ion <Landé g-factor> is $4/5$ and its <effective paramagnetic moment> is $(4/5)\sqrt{20}\,\mu_B\simeq3.58\mu_B$.