Protactinium-231

Properties and data of the isotope ²³¹Pa.

Content

General Data

Radioactive Decay

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

See also: list of Protactinium isotopes.

General data

Name of the isotope:Protactinium-231; Pa-231Symbol:²³¹Pa or 23191PaMass number A:231 (= number of nucleons)Atomic number Z:91 (= number of protons)Neutrons N:140Isotopic mass:231.0358826(19) u (atomic weight of Protactinium-231)Nuclide mass:230.9859683 u (calculated nuclear mass without electrons)Mass excess:33.42443 MeVMass defect:1.889283552 u (per nucleus)Nuclear binding energy:1759.85629299 MeV (per nucleus)
7.61842551 MeV (average binding energy per nucleon)Separation energy:S_N = 6.821(3) MeV (first neutron)
S_P = 4.7272(15) MeV (first proton)Half-life:3.276(11) × 10⁴ aDecay constant λ:6.709261078673 × 10^-13 s^-1Specific activity α:1749095899.6478 Bq g^-1
0.047272862152643 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Magnetic dipole moment:μ(μ_N) = 2.01(2)Year of discovery:1918

Radioactive Decay

Half-life T_½ = 3.276(11) × 10⁴ a respectively 1.03312 × 10¹² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²²⁷Ac	ca. 100 %	5.1499(8) MeV
SZ	div	<<< 1 %

Parent Nuclides

Direct parent isotopes are: ²³⁵Np, ²³¹U, ²³¹Th.

Occurrence

Comparison of the natural Protactinium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Protactinium Isotopic mixture	231.03588 u	100 %
Isotope ²³¹Pa	231.0358826(19) u	100 %	3.276(11) × 10⁴ a	3/2-

NMR data

Nuclear magnetic properties of the NMR active Nuclide ²³¹Pa

Isotope:²³¹Pa-NMRQuantity:100 %Spin:3/2-Nuclearmagnetic moment
μ/μ_N:2.01(2)Gyromagnetic ratio γ:0.40 · 10⁷ rad T^-1 s^-1Nuclear g-factor:g_l = 1.34Quadrupole moment Q:-1.72(5) barn (100 fm²)Line width parameter (factor):l = 39445.33 fm⁴Resonance frequency:v₀ = 10.2 at 1 TRelative Sensitivity:0.06903 (H₀ = const.)
1.1995 (v₀ = const.)
[related to ¹H = 1.000]

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 140) and isobaric (same nucleon number A = 231) with Protactinium-231. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 140	Isobar A = 231
83	²²³Bi
84	²²⁴Po
85	²²⁵At
86	²²⁶Rn
87	²²⁷Fr	²³¹Fr
88	²²⁸Ra	²³¹Ra
89	²²⁹Ac	²³¹Ac
90	²³⁰Th	²³¹Th
91	²³¹Pa	²³¹Pa
92	²³²U	²³¹U
93	²³³Np	²³¹Np
94	²³⁴Pu	²³¹Pu
95	²³⁵Am	²³¹Am
96	²³⁶Cm
97	²³⁷Bk
98	²³⁸Cf

External data and identifiers

CAS:14331-85-2InChI Key:XLROVYAPLOFLNU-IGMARMGPSA-NSMILES:[231Pa]PubChem:ID 105147Adopted Levels, Gammas:NuDat 231Pa

Literature and References

[1] - G. G. Kulikov, E. G. Kulikov, A. N. Shmelev, V. A. Apse:
Protactinium-231 – New burnable neutron absorber.
In: Nuclear Energy and Technology, (2017), DOI 10.1016/j.nucet.2017.10.002.

[2] - S. M.Jerome, S. M.Collins, S. Happel, P. Ivanov, B. C. Russell:
Isolation and purification of protactinium-231.
In: Applied Radiation and Isotopes, (2018), DOI 10.1016/j.apradiso.2017.07.051.