Polonium-215

Properties and data of the isotope ²¹⁵Po.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Polonium-215; Po-215Other names:Actinium ASymbol:²¹⁵Po or 21584PoMass number A:215 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:131Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5595238095238 (= neutron-proton ratio)Neutron excess (N-Z):47Isotopic mass:214.9994185(23) u (atomic weight of Polonium-215)Nuclide mass:214.9533432 u (calculated nuclear mass without electrons)Mass excess:-0.54166 MeVMass defect:1.792988184 u (per nucleus)Nuclear binding energy:1670.15773547 MeV (per nucleus)
7.76817551 MeV (average binding energy per nucleon)Separation energy:S_N = 4.1430(25) MeV (first neutron)
S_P = 6.630(11) MeV (first proton)Half-life:1.781(4) msDecay constant λ:389.18988240311 s^-1Specific activity α:1.095213221071 × 10⁺²⁴ Bq g^-1
29600357326268 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Year of discovery:1911

Radioactive Decay

Half-life T_½ = 1.781(4) ms respectively 1.781 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹¹Pb	99.99977(2) %	7.5263(8) MeV
β^-	²¹⁵At	0.00023(2) %	0.714(7) MeV

Parent Nuclides

Direct parent isotopes are: ²¹⁹Rn, ²¹⁵Bi.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 131) and isobaric (same nucleon number A = 215) with Polonium-215. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 131	Isobar A = 215
79	²¹⁰Au
80	²¹¹Hg	²¹⁵Hg
81	²¹²Tl	²¹⁵Tl
82	²¹³Pb	²¹⁵Pb
83	²¹⁴Bi	²¹⁵Bi
84	²¹⁵Po	²¹⁵Po
85	²¹⁶At	²¹⁵At
86	²¹⁷Rn	²¹⁵Rn
87	²¹⁸Fr	²¹⁵Fr
88	²¹⁹Ra	²¹⁵Ra
89	²²⁰Ac	²¹⁵Ac
90	²²¹Th	²¹⁵Th
91	²²²Pa	²¹⁵Pa
92	²²³U	²¹⁵U
93	²²⁴Np