Radon-201m

Properties and data of the isotope ^201mRn.

Contents

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

General data

Name of the isotope:Radon-201m; Rn-201mSymbol:^201mRn or 201m86RnMass number A:201 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:115Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.3372093023256 (= neutron-proton ratio)Neutron excess (N-Z):29Excitation energy:0 + x keVIsotopic mass:200.99563(5) u (atomic weight of Radon-201m)Nuclide mass:200.9484578 u (calculated nuclear mass without electrons)Mass excess:-4.07063 MeVMass defect:1.673788092 u (per nucleus)Nuclear binding energy:1559.12356497 MeV (per nucleus)
7.75683366 MeV (average binding energy per nucleon)Half-life:3.8(1) sDecay constant λ:0.18240715277893 s^-1Specific activity α:5.492407839473 × 10⁺²⁰ Bq g^-1
14844345512.091 Ci g^-1Spin and parity:
(nuclear angular momentum)(13/2+)

Radioactive Decay

Half-life T_½ = 3.8(1) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹⁷Po	?
EC/β⁺	²⁰¹At	?

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
²⁰¹Rn		7.0(4) s	(3/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 115) and isobaric (same nucleon number A = 201) with Radon-201m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 115	Isobar A = 201
70	¹⁸⁵Yb
71	¹⁸⁶Lu
72	¹⁸⁷Hf
73	¹⁸⁸Ta
74	¹⁸⁹W
75	¹⁹⁰Re
76	¹⁹¹Os	²⁰¹Os
77	¹⁹²Ir	²⁰¹Ir
78	¹⁹³Pt	²⁰¹Pt
79	¹⁹⁴Au	²⁰¹Au
80	¹⁹⁵Hg	²⁰¹Hg
81	¹⁹⁶Tl	²⁰¹Tl
82	¹⁹⁷Pb	²⁰¹Pb
83	¹⁹⁸Bi	²⁰¹Bi
84	¹⁹⁹Po	²⁰¹Po
85	²⁰⁰At	²⁰¹At
86	²⁰¹Rn	²⁰¹Rn
87	²⁰²Fr	²⁰¹Fr
88	²⁰³Ra	²⁰¹Ra
89	²⁰⁴Ac