Isotope Mass Abundance Spin Mag Moment
141Pr 140.907647 100% 5/2 +4.3
Pr I Ground State (1s22s22p63s23p63d104s24p64d105s25p6)4f36s2 4I°9/2 Ionization energy 44140 cm-1 (5.473 eV) Ref. WSPC78 Pr II Ground State (1s22s22p63s23p63d104s24p64d105s25p6)4f3(4I°9/2)6s (9/2,1/2)°4 Ionization energy 85100 cm-1 (10.55 eV) Ref. SR65