Thallium-215

Properties and data of the isotope ²¹⁵Tl.

Content

General data

Name of the isotope:Thallium-215; Tl-215Symbol:²¹⁵Tl or 21581TlMass number A:215 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:134Isotopic mass:215.01064(32) u (atomic weight of Thallium-215)Nuclide mass:214.96621 u (calculated nuclear mass without electrons)Mass excess:9.9111 MeVMass defect:1.784286336 u (per nucleus)Nuclear binding energy:1662.05201627 MeV (per nucleus)
7.73047449 MeV (average binding energy per nucleon)Separation energy:S_N = 4.62(36) MeV (first neutron)
S_P = 8.56(50) MeV (first proton)Half-life:> 300 nsDecay constant λ:2310490.6018665 s^-1Specific activity α:6.471674353488 × 10⁺²⁷ Bq g^-1
1.749101176618 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:2010

Radioactive Decay

Half-life T_½ = > 300 ns respectively 3.0 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²¹⁵Pb	?	5.57(30) MeV
β^-, n	²¹⁴Pb	?	2.02(30) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 134) and isobaric (same nucleon number A = 215) with Thallium-215. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 134	Isobar A = 215
80	²¹⁴Hg	²¹⁵Hg
81	²¹⁵Tl	²¹⁵Tl
82	²¹⁶Pb	²¹⁵Pb
83	²¹⁷Bi	²¹⁵Bi
84	²¹⁸Po	²¹⁵Po
85	²¹⁹At	²¹⁵At
86	²²⁰Rn	²¹⁵Rn
87	²²¹Fr	²¹⁵Fr
88	²²²Ra	²¹⁵Ra
89	²²³Ac	²¹⁵Ac
90	²²⁴Th	²¹⁵Th
91	²²⁵Pa	²¹⁵Pa
92	²²⁶U	²¹⁵U
93	²²⁷Np
94	²²⁸Pu
95	²²⁹Am