Lead-216m

Properties and data of the isotope ^216mPb.

Contents

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

General data

Name of the isotope:Lead-216m; Pb-216mSymbol:^216mPb or 216m82PbMass number A:216 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:134Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.6341463414634 (= neutron-proton ratio)Neutron excess (N-Z):52Excitation energy:1459+x keVIsotopic mass:216.00803(21) u (atomic weight of Lead-216m)Nuclide mass:215.9630516 u (calculated nuclear mass without electrons)Mass excess:7.4799 MeVMass defect:1.794721368 u (per nucleus)Nuclear binding energy:1671.77218596 MeV (per nucleus)
7.73968605 MeV (average binding energy per nucleon)Half-life:0.40(4) μsDecay constant λ:1732867.9513999 s^-1Specific activity α:4.831284673611 × 10⁺²⁷ Bq g^-1
1.305752614489 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)(8+)

Radioactive Decay

Half-life T_½ = 0.40(4) μs respectively 4.0 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²¹⁶Pb	100 %

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
²¹⁶Pb		300 ns	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 134) and isobaric (same nucleon number A = 216) with Lead-216m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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