Radon-215

Properties and data of the isotope ²¹⁵Rn.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Radon-215 is a radioisotope of the chemical element radon, which has 129 neutrons in its atomic nucleus in addition to the element-specific 86 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 215. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²¹⁵Rn is exclusively for academic purposes.

The radioactive isotope was discovered in 1951; it occurs as a decay product in the decay series that starts from uranium-227 [1].²¹⁵Rn was then called emanation-215 (²¹⁵Em).

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

General data

Name of the isotope:Radon-215; Rn-215Symbol:²¹⁵Rn or 21586RnMass number A:215 (= number of nucleons)Atomic number Z:86 (= number of protons)Neutrons N:129Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5 (= neutron-proton ratio)Neutron excess (N-Z):43Isotopic mass:214.998745(7) u (atomic weight of Radon-215)Nuclide mass:214.9515728 u (calculated nuclear mass without electrons)Mass excess:-1.16902 MeVMass defect:1.791981916 u (per nucleus)Nuclear binding energy:1669.22040286 MeV (per nucleus)
7.76381583 MeV (average binding energy per nucleon)Separation energy:S_N = 4.921(11) MeV (first neutron)
S_P = 5.079(7) MeV (first proton)Half-life:2.30(10) μsDecay constant λ:301368.33937389 s^-1Specific activity α:8.480759768386 × 10⁺²⁶ Bq g^-1
2.292097234699 × 10⁺¹⁶ Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Year of discovery:1951

Radioactive Decay

Radon-215 decays to polonium-211 by emitting α-particles (helium-4 nuclei).

Half-life T_½ = 2.30(10) μs respectively 2.30 × 10^-6 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹¹Po	100 %	8.839(6) MeV

Parent Nuclides

Direct parent isotope is: ²¹⁹Ra.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 129) and isobaric (same nucleon number A = 215) with Radon-215. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 129	Isobar A = 215
78	²⁰⁷Pt
79	²⁰⁸Au
80	²⁰⁹Hg	²¹⁵Hg
81	²¹⁰Tl	²¹⁵Tl
82	²¹¹Pb	²¹⁵Pb
83	²¹²Bi	²¹⁵Bi
84	²¹³Po	²¹⁵Po
85	²¹⁴At	²¹⁵At
86	²¹⁵Rn	²¹⁵Rn
87	²¹⁶Fr	²¹⁵Fr
88	²¹⁷Ra	²¹⁵Ra
89	²¹⁸Ac	²¹⁵Ac
90	²¹⁹Th	²¹⁵Th
91	²²⁰Pa	²¹⁵Pa
92	²²¹U	²¹⁵U
93	²²²Np

External data and identifiers

Adopted Levels, Gammas:NuDat 215Rn

Literature and References

[1] - W. W. Meinke, A. Ghiorso, G. T. Seaborg:
Further Work on Heavy Collateral Radioactive Chains.
In: Physical Review, 85, 429, (1952), DOI 10.1103/PhysRev.85.429.