Thorium-210

Properties and data of the isotope ²¹⁰Th.

Content

General data

Name of the isotope:Thorium-210; Th-210Symbol:²¹⁰Th or 21090ThMass number A:210 (= number of nucleons)Atomic number Z:90 (= number of protons)Neutrons N:120Isotopic mass:210.015093(20) u (atomic weight of Thorium-210)Nuclide mass:209.9657272 u (calculated nuclear mass without electrons)Mass excess:14.05904 MeVMass defect:1.7289498 u (per nucleus)Nuclear binding energy:1610.506365 MeV (per nucleus)
7.66907793 MeV (average binding energy per nucleon)Separation energy:S_N = 10.38(14) MeV (first neutron)
S_P = 2.07(5) MeV (first proton)Half-life:1.6(4) msDecay constant λ:433.21698784997 s^-1Specific activity α:1.242330344642 × 10⁺²⁴ Bq g^-1
33576495801159 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1995

Radioactive Decay

Half-life T_½ = 1.6(4) ms respectively 1.6 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁰⁶Ra	99 %	8.069(6) MeV
EE/β⁺	²¹⁰Ac	ca. 1 %	5.27(6) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 120) and isobaric (same nucleon number A = 210) with Thorium-210. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 120	Isobar A = 210
73	¹⁹³Ta
74	¹⁹⁴W
75	¹⁹⁵Re
76	¹⁹⁶Os
77	¹⁹⁷Ir
78	¹⁹⁸Pt
79	¹⁹⁹Au	²¹⁰Au
80	²⁰⁰Hg	²¹⁰Hg
81	²⁰¹Tl	²¹⁰Tl
82	²⁰²Pb	²¹⁰Pb
83	²⁰³Bi	²¹⁰Bi
84	²⁰⁴Po	²¹⁰Po
85	²⁰⁵At	²¹⁰At
86	²⁰⁶Rn	²¹⁰Rn
87	²⁰⁷Fr	²¹⁰Fr
88	²⁰⁸Ra	²¹⁰Ra
89	²⁰⁹Ac	²¹⁰Ac
90	²¹⁰Th	²¹⁰Th