Thorium-219

Properties and data of the isotope ²¹⁹Th.

Content

General data

Name of the isotope:Thorium-219; Th-219Symbol:²¹⁹Th or 21990ThMass number A:219 (= number of nucleons)Atomic number Z:90 (= number of protons)Neutrons N:129Isotopic mass:219.01554(5) u (atomic weight of Thorium-219)Nuclide mass:218.9661742 u (calculated nuclear mass without electrons)Mass excess:14.47542 MeVMass defect:1.806487044 u (per nucleus)Nuclear binding energy:1682.73184256 MeV (per nucleus)
7.68370704 MeV (average binding energy per nucleon)Separation energy:S_N = 5.97(5) MeV (first neutron)
S_P = 3.66(7) MeV (first proton)Half-life:1.05(3) μsDecay constant λ:660140.17196185 s^-1Specific activity α:1.815277215916 × 10⁺²⁷ Bq g^-1
4.906154637612 × 10⁺¹⁶ Ci g^-1Spin and parity:
(nuclear angular momentum)(9/2+)Year of discovery:1973

Radioactive Decay

Half-life T_½ = 1.05(3) μs respectively 1.05 × 10^-6 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹⁵Ra	100 %	9.51(5) MeV

Parent Nuclides

Direct parent isotope is: ²²³U.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 129) and isobaric (same nucleon number A = 219) with Thorium-219. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 129	Isobar A = 219
78	²⁰⁷Pt
79	²⁰⁸Au
80	²⁰⁹Hg
81	²¹⁰Tl
82	²¹¹Pb	²¹⁹Pb
83	²¹²Bi	²¹⁹Bi
84	²¹³Po	²¹⁹Po
85	²¹⁴At	²¹⁹At
86	²¹⁵Rn	²¹⁹Rn
87	²¹⁶Fr	²¹⁹Fr
88	²¹⁷Ra	²¹⁹Ra
89	²¹⁸Ac	²¹⁹Ac
90	²¹⁹Th	²¹⁹Th
91	²²⁰Pa	²¹⁹Pa
92	²²¹U	²¹⁹U