Neodymium-146

Main isotopes of neodymium

Iso­tope Decay abun­dance half-life mode energy (MeV) pro­duct 142Nd 27.2% is stable with 82 neutrons 143Nd 12.2% is stable with 83 neutrons 144Nd 23.8% 2.29×1015 y α 1.905 140Ce 145Nd 8.3% is stable with 85 neutrons 146Nd 17.2% is stable with 86 neutrons 148Nd 5.8% is stable with 88 neutrons 150Nd 5.6% 6.7×1018 y β−β− 3.367 150Sm
Standard atomic weight (Ar)	144.242(3)

Naturally occurring neodymium (₆₀Nd) is composed of 5 stable isotopes, ¹⁴²Nd, ¹⁴³Nd, ¹⁴⁵Nd, ¹⁴⁶Nd and ¹⁴⁸Nd, with ¹⁴²Nd being the most abundant (27.2% natural abundance), and 2 long-lived radioisotopes, ¹⁴⁴Nd and ¹⁵⁰Nd. In all, 33 radioisotopes of Neodymium have been characterized up to now, with the most stable being naturally occurring isotopes ¹⁴⁴Nd (alpha decay, a half-life (t_1/2) of 2.29×10¹⁵ years) and ¹⁵⁰Nd (double beta decay, t_1/2 of 7×10¹⁸ years). All of the remaining radioactive isotopes have half-lives that are less than 11 days, and the majority of these have half-lives that are less than 70 seconds. This element also has 13 known meta states with the most stable being ^139mNd (t_1/2 5.5 hours), ^135mNd (t_1/2 5.5 minutes) and ^133m1Nd (t_1/2 ~70 seconds).

The primary decay modes before the most abundant stable isotope, ¹⁴²Nd, are electron capture and positron decay, and the primary mode after is beta decay. The primary decay products before ¹⁴²Nd are element Pr (praseodymium) isotopes and the primary products after are element Pm (promethium) isotopes.

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