Praseodymium-129

Properties and data of the isotope ¹²⁹Pr.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

See also: list of Praseodymium isotopes.

General data

Name of the isotope:Praseodymium-129; Pr-129Symbol:¹²⁹Pr or 12959PrMass number A:129 (= number of nucleons)Atomic number Z:59 (= number of protons)Neutrons N:70Isotopic mass:128.92509(3) u (atomic weight of Praseodymium-129)Nuclide mass:128.8927262 u (calculated nuclear mass without electrons)Mass excess:-69.77822 MeVMass defect:1.143131008 u (per nucleus)Nuclear binding energy:1064.81967517 MeV (per nucleus)
8.25441609 MeV (average binding energy per nucleon)Separation energy:S_N = 11.51(4) MeV (first neutron)
S_P = 1.53(4) MeV (first proton)Half-life:30(4) sDecay constant λ:0.023104906018665 s^-1Specific activity α:1.087039051562 × 10⁺²⁰ Bq g^-1
2937943382.6014 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2+)Year of discovery:1977

Radioactive Decay

Half-life T_½ = 30(4) s respectively 3.0 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹²⁹Ce	100 %	6.51(4) MeV

Parent Nuclides

Direct parent isotope is: ¹²⁹Nd.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^129mPr	382.7(5) keV	1~ ms	(11/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 70) and isobaric (same nucleon number A = 129) with Praseodymium-129. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 70	Isobar A = 129
39	¹⁰⁹Y
40	¹¹⁰Zr
41	¹¹¹Nb
42	¹¹²Mo
43	¹¹³Tc
44	¹¹⁴Ru
45	¹¹⁵Rh
46	¹¹⁶Pd	¹²⁹Pd
47	¹¹⁷Ag	¹²⁹Ag
48	¹¹⁸Cd	¹²⁹Cd
49	¹¹⁹In	¹²⁹In
50	¹²⁰Sn	¹²⁹Sn
51	¹²¹Sb	¹²⁹Sb
52	¹²²Te	¹²⁹Te
53	¹²³I	¹²⁹I
54	¹²⁴Xe	¹²⁹Xe
55	¹²⁵Cs	¹²⁹Cs
56	¹²⁶Ba	¹²⁹Ba
57	¹²⁷La	¹²⁹La
58	¹²⁸Ce	¹²⁹Ce
59	¹²⁹Pr	¹²⁹Pr
60	¹³⁰Nd	¹²⁹Nd
61	¹³¹Pm	¹²⁹Pm
62	¹³²Sm	¹²⁹Sm
63	¹³³Eu
64	¹³⁴Gd
65	¹³⁵Tb