Thorium-230

Properties and data of the isotope ²³⁰Th.

Content

General data

Name of the isotope:Thorium-230; Th-230Other names:Ionium. IoSymbol:²³⁰Th or 23090ThMass number A:230 (= number of nucleons)Atomic number Z:90 (= number of protons)Neutrons N:140Isotopic mass:230.0331323(2) u (atomic weight of Thorium-230)Nuclide mass:229.9837665 u (calculated nuclear mass without electrons)Mass excess:30.86254 MeVMass defect:1.88420882 u (per nucleus)Nuclear binding energy:1755.12921058 MeV (per nucleus)
7.63099657 MeV (average binding energy per nucleon)Separation energy:S_N = 6.7943(22) MeV (first neutron)
S_P = 7.116(12) MeV (first proton)Cross section:σ(n.γ) = 23.4(5) barn (thermal neutron capture cross-section)
σ(n.f) < 0.5 mb (gap cross-section)Half-life:7.54(3) × 10⁴ aDecay constant λ:2.913068539488 × 10^-13 s^-1Specific activity α:762735177.36727 Bq g^-1
0.020614464253169 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.7670(131) femtometer fmYear of discovery:1907

Radioactive Decay

Half-life T_½ = 7.54(3) × 10⁴ a respectively 2.37944 × 10¹² seconds s.

Decay mode	Daughter	Probability	Decay energy
α	²²⁶Ra	ca. 100 %	4.7700(15) MeV
SZ	div	<< 1 %
CZ	²⁴Ne	<< 1 %

Parent Nuclides

Direct parent isotopes are: ²³⁴U, ²³⁰Ac, ²³⁰Pa.

Occurrence

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

	Atomic Mass m_a	Quantity	Half-life	Spin
Thorium Isotopic mixture	232.0377 u	100 %
Isotope ²³⁰Th	230.0331323(2) u	0.02(2) %	7.54(3) × 10⁴ a	0+
Isotope ²³²Th	232.03806(2) u	99.98(2) %	1.40(1) × 10¹⁰ a	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 140) and isobaric (same nucleon number A = 230) with Thorium-230. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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