Thallium-217

Properties and data of the isotope ²¹⁷Tl.

Contents

See also: List of individual Thallium isotopes (and general data sources).

General data

Name of the isotope:Thallium-217; Tl-217Symbol:²¹⁷Tl or 21781TlMass number A:217 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:136Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.679012345679 (= neutron-proton ratio)Neutron excess (N-Z):55Isotopic mass:217.01966(43) u (atomic weight of Thallium-217)Nuclide mass:216.97523 u (calculated nuclear mass without electrons)Mass excess:18.31317 MeVMass defect:1.792596168 u (per nucleus)Nuclear binding energy:1669.79257492 MeV (per nucleus)
7.69489666 MeV (average binding energy per nucleon)Separation energy:S_N = 4.48(50) MeV (first neutron)
S_P = 8.83(57) MeV (first proton)Half-life:> 300 nsDecay constant λ:2310490.6018665 s^-1Specific activity α:6.412027585253 × 10⁺²⁷ Bq g^-1
1.732980428446 × 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^-	²¹⁷Pb		6.07(50) MeV
β^-, n	²¹⁶Pb	?	2.76(45) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 136) and isobaric (same nucleon number A = 217) with Thallium-217. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 136	Isobar A = 217
80	²¹⁶Hg
81	²¹⁷Tl	²¹⁷Tl
82	²¹⁸Pb	²¹⁷Pb
83	²¹⁹Bi	²¹⁷Bi
84	²²⁰Po	²¹⁷Po
85	²²¹At	²¹⁷At
86	²²²Rn	²¹⁷Rn
87	²²³Fr	²¹⁷Fr
88	²²⁴Ra	²¹⁷Ra
89	²²⁵Ac	²¹⁷Ac
90	²²⁶Th	²¹⁷Th
91	²²⁷Pa	²¹⁷Pa
92	²²⁸U	²¹⁷U
93	²²⁹Np
94	²³⁰Pu
95	²³¹Am
96	²³²Cm
97	²³³Bk