Radium-216

Properties and data of the isotope ²¹⁶Ra.

Content

General data

Name of the isotope:Radium-216; Ra-216Symbol:²¹⁶Ra or 21688RaMass number A:216 (= number of nucleons)Atomic number Z:88 (= number of protons)Neutrons N:128Isotopic mass:216.003533(9) u (atomic weight of Radium-216)Nuclide mass:215.955264 u (calculated nuclear mass without electrons)Mass excess:3.29097 MeVMass defect:1.794179064 u (per nucleus)Nuclear binding energy:1671.26703304 MeV (per nucleus)
7.73734738 MeV (average binding energy per nucleon)Separation energy:S_N = 7.314(11) MeV (first neutron)
S_P = 7.73735(4) MeV (first proton)Half-life:182(10) nsDecay constant λ:3808500.9920876 s^-1Specific activity α:1.061820807387 × 10⁺²⁸ Bq g^-1
2.869785965911 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1972

Radioactive Decay

Half-life T_½ = 182(10) ns respectively 1.82 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹²Rn	~100%	9.526(8) MeV
EE	²¹⁶Fr	> 0%	0.32(1) MeV

Parent Nuclides

Direct parent isotope is: ²²⁰Th.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 128) and isobaric (same nucleon number A = 216) with Radium-216. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 128	Isobar A = 216
77	²⁰⁵Ir
78	²⁰⁶Pt
79	²⁰⁷Au
80	²⁰⁸Hg	²¹⁶Hg
81	²⁰⁹Tl	²¹⁶Tl
82	²¹⁰Pb	²¹⁶Pb
83	²¹¹Bi	²¹⁶Bi
84	²¹²Po	²¹⁶Po
85	²¹³At	²¹⁶At
86	²¹⁴Rn	²¹⁶Rn
87	²¹⁵Fr	²¹⁶Fr
88	²¹⁶Ra	²¹⁶Ra
89	²¹⁷Ac	²¹⁶Ac
90	²¹⁸Th	²¹⁶Th
91	²¹⁹Pa	²¹⁶Pa
92	²²⁰U	²¹⁶U
95	²²³Am