Plutonium-242

Properties and data of the isotope ²⁴²Pu.

Contents

Plutonium-242 is the radioisotope of the element plutonium, whose atomic nucleus has 148 neutrons in addition to the element-specific 94 protons, resulting in a mass number of 242.

See also: List of individual Plutonium isotopes (and general data sources).

General data

Name of the isotope:Plutonium-242; Pu-242Symbol:²⁴²Pu or 24294PuMass number A:242 (= number of nucleons)Atomic number Z:94 (= number of protons)Neutrons N:148Isotopic mass:242.0587410(13) u (atomic weight of Plutonium-242)Nuclide mass:242.0071815 u (calculated nuclear mass without electrons)Mass excess:54.71689 MeVMass defect:1.959219576 u (per nucleus)Nuclear binding energy:1825.00127973 MeV (per nucleus)
7.5413276 MeV (average binding energy per nucleon)Separation energy:S_N = 6.3096(7) MeV (first neutron)
S_P = 6.83(7) MeV (first proton)Half-life:375000 aDecay constant λ:5.861214109250 × 10^-14 s^-1Specific activity α:145855607.33948 Bq g^-1
0.0039420434416076 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.8823(380) femtometer fmYear of discovery:1950

Radioactive Decay

Half-life T_½ = 375000 a respectively 1.1826 × 10¹³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²³⁸U	ca. 100 %	4.9842(10) MeV
SZ	^div	trace

Graphic representation of the radioactive decay chain emanating from the isotope plutonium-242, which continues from Uranium-238 in the uranium-radium series.

Parent Nuclides

Direct parent isotopes are: ²⁴²Am, ²⁴²Np, ²⁴⁶Cm.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 148) and isobaric (same nucleon number A = 242) with Plutonium-242. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 148	Isobar A = 242
90	²³⁸Th
91	²³⁹Pa
92	²⁴⁰U	²⁴²U
93	²⁴¹Np	²⁴²Np
94	²⁴²Pu	²⁴²Pu
95	²⁴³Am	²⁴²Am
96	²⁴⁴Cm	²⁴²Cm
97	²⁴⁵Bk	²⁴²Bk
98	²⁴⁶Cf	²⁴²Cf
99	²⁴⁷Es	²⁴²Es
100	²⁴⁸Fm	²⁴²Fm
101	²⁴⁹Md
102	²⁵⁰No
103	²⁵¹Lr
104	²⁵²Rf