Neodymium-129

Properties and data of the isotope ¹²⁹Nd.

Content

General data

Name of the isotope:Neodymium-129; Nd-129Symbol:¹²⁹Nd or 12960NdMass number A:129 (= number of nucleons)Atomic number Z:60 (= number of protons)Neutrons N:69Isotopic mass:128.93310(22) u (atomic weight of Neodymium-129)Nuclide mass:128.9001877 u (calculated nuclear mass without electrons)Mass excess:-62.31695 MeVMass defect:1.134281124 u (per nucleus)Nuclear binding energy:1056.57606132 MeV (per nucleus)
8.1905121 MeV (average binding energy per nucleon)Separation energy:S_N = 10.07(28) MeV (first neutron)
S_P = 3.27(20) MeV (first proton)Half-life:6.7(4) sDecay constant λ:0.10345480306865 s^-1Specific activity α:4.86733903684 × 10⁺²⁰ Bq g^-1
13154970369.857 Ci g^-1Spin and parity:
(nuclear angular momentum)(5/2+)Year of discovery:1977

Radioactive Decay

Half-life T_½ = 6.7(4) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹²⁹Pr	100 %	7.46(20) MeV
EE, p	¹²⁸Ce	> 0 %

Parent Nuclides

Direct parent isotope is: ¹²⁹Pm.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 69) and isobaric (same nucleon number A = 129) with Neodymium-129. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 69	Isobar A = 129
38	¹⁰⁷Sr
39	¹⁰⁸Y
40	¹⁰⁹Zr
41	¹¹⁰Nb
42	¹¹¹Mo
43	¹¹²Tc
44	¹¹³Ru
45	¹¹⁴Rh
46	¹¹⁵Pd	¹²⁹Pd
47	¹¹⁶Ag	¹²⁹Ag
48	¹¹⁷Cd	¹²⁹Cd
49	¹¹⁸In	¹²⁹In
50	¹¹⁹Sn	¹²⁹Sn
51	¹²⁰Sb	¹²⁹Sb
52	¹²¹Te	¹²⁹Te
53	¹²²I	¹²⁹I
54	¹²³Xe	¹²⁹Xe
55	¹²⁴Cs	¹²⁹Cs
56	¹²⁵Ba	¹²⁹Ba
57	¹²⁶La	¹²⁹La
58	¹²⁷Ce	¹²⁹Ce
59	¹²⁸Pr	¹²⁹Pr
60	¹²⁹Nd	¹²⁹Nd
61	¹³⁰Pm	¹²⁹Pm
62	¹³¹Sm	¹²⁹Sm
63	¹³²Eu