Radon-207m

Properties and data of the isotope ²⁰⁷Rn.

Content

General data

Name of the isotope:Radon-207m; Rn-207mSymbol:²⁰⁷Rn or 20786RnMass number A:207 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:121Isotopic mass:206.990730(9) u (atomic weight of Radon-207m)
Excitation energy: 899.1(10) keVNuclide mass:206.9435578 u (calculated nuclear mass without electrons)Mass excess:-8.63495 MeVMass defect:1.730677588 u (per nucleus)Nuclear binding energy:1612.11578916 MeV (per nucleus)
7.78799898 MeV (average binding energy per nucleon)Half-life:184.5(9) μsDecay constant λ:2436.3697031984 s^-1Specific activity α:7.122408514341 × 10⁺²⁴ Bq g^-1
1.924975274146 × 10⁺¹⁴ Ci g^-1Spin and parity:
(nuclear angular momentum)13/2+Magnetic dipole moment:μ(μ_N) = - 0.903(3)Nuclear g-factor:g_l = -0.13892307692308

Radioactive Decay

Half-life T_½ = 184.5(9) μs respectively 2.845 × 10^-4 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²⁰⁷Rn	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
²⁰⁷Rn		9.25(17) min	5/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 121) and isobaric (same nucleon number A = 207) with Radon-207m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 121	Isobar A = 207
73	¹⁹⁴Ta
74	¹⁹⁵W
75	¹⁹⁶Re
76	¹⁹⁷Os
77	¹⁹⁸Ir
78	¹⁹⁹Pt	²⁰⁷Pt
79	²⁰⁰Au	²⁰⁷Au
80	²⁰¹Hg	²⁰⁷Hg
81	²⁰²Tl	²⁰⁷Tl
82	²⁰³Pb	²⁰⁷Pb
83	²⁰⁴Bi	²⁰⁷Bi
84	²⁰⁵Po	²⁰⁷Po
85	²⁰⁶At	²⁰⁷At
86	²⁰⁷Rn	²⁰⁷Rn
87	²⁰⁸Fr	²⁰⁷Fr
88	²⁰⁹Ra	²⁰⁷Ra
89	²¹⁰Ac	²⁰⁷Ac
90	²¹¹Th	²⁰⁷Th
91	²¹²Pa