Radium-223

Properties and data of the isotope ²²³Ra.

Contents

General Data

Radioactive Decay

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

Radium-223 is the radioactive isotope of the chemical element radium with the mass number 223; The atomic nucleus of the nuclide has 88 protons and 135 neutrons.

The radionuclide radium-223 was discovered in 1905 by T. Godlewski, a Polish chemist from Kraków. It was known at the time as Actinium X, with the symbol AcX.

The main use of radium-223 is as a radiopharmaceutical for the treatment of metastatic bone cancer. The chemical similarity of radium-223 to calcium and the short range of its emitted alpha radiation to tumor tissue are responsible for its medical effect. The corresponding active ingredient is radium-223 dichloride (trade name Xofigo®).

Although radium-223 is formed naturally in trace amounts by the decay of uranium-235, the amounts needed by humans are generally produced artificially. This is done by bombarding the naturally occurring isotope radium-226 with neutrons. This initially produces radium-227, which eventually decays to radium-223 via the radionuclides actinium-227 and thorium-227. A corresponding 227Ac/223Ra generator continuously provides the small amounts of the radionuclide needed for nuclear medicine.

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

General data

Name of the isotope:Radium-223; Ra-223Other names:Actinium XSymbol:²²³Ra or 22388RaMass number A:223 (= number of nucleons)Atomic number Z:88 (= number of protons)Neutrons N:135Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5340909090909 (= neutron-proton ratio)Neutron excess (N-Z):47Isotopic mass:223.0185006(22) u (atomic weight of Radium-223)Nuclide mass:222.9702316 u (calculated nuclear mass without electrons)Mass excess:17.2332 MeVMass defect:1.839865876 u (per nucleus)Nuclear binding energy:1713.8240243 MeV (per nucleus)
7.68530953 MeV (average binding energy per nucleon)Separation energy:S_N = 5.158(5) MeV (first neutron)
S_P = 6.434(8) MeV (first proton)Cross section:σ(n.γ) = 130(20) barn (thermal neutron capture cross-section)Half-life:11.43(5) dDecay constant λ:7.018842355237 × 10^-7 s^-1Specific activity α:1.895446517351 × 10⁺¹⁵ Bq g^-1
51228.284252732 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = + 0.2705(19)Charge radius:5.6973(253) femtometer fmYear of discovery:1905

Radioactive Decay

Radium-223 emits α-radiation and decays radioactively via several intermediates to the stable lead-207 (see figure).

Half-life T_½ = 11.43(5) d respectively 9.87552 × 10⁵ seconds s.

Decay mode	Daughter	Probability	Decay energy
α	²¹⁹Rn	100%	5.97899(21) MeV
CD	²⁰⁹Pb	rare	-
+	¹⁴C	rare	-

The diagram shows the radioactive decay scheme of the radionuclide radium-223. The end product of the decay chain is the stable isotope lead-207.

Parent Nuclides

Direct parent isotopes are: ²²⁷Th, ²²³Ac, ²²³Fr.

NMR data

Nuclear magnetic properties and parameters of the NMR active Nuclide ²²³Ra

Isotope:²²³Ra-NMRQuantity:Does not occur in nature!Spin:3/2+Nuclearmagnetic moment
μ/μ_N:+ 0.2705(19)Nuclear g-factor:g_l = 0.18033333333333Quadrupole moment Q:+ 1.254(3) barn (100 fm²)Resonance frequency:v₀ = 1.3746 MHz at 1 TRelative Sensitivity:[related to ¹H = 1.000]:
0.00017 (H₀ = const.)
0.1614 (v₀ = const.)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 135) and isobaric (same nucleon number A = 223) with Radium-223. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 135	Isobar A = 223
80	²¹⁵Hg
81	²¹⁶Tl
82	²¹⁷Pb
83	²¹⁸Bi	²²³Bi
84	²¹⁹Po	²²³Po
85	²²⁰At	²²³At
86	²²¹Rn	²²³Rn
87	²²²Fr	²²³Fr
88	²²³Ra	²²³Ra
89	²²⁴Ac	²²³Ac
90	²²⁵Th	²²³Th
91	²²⁶Pa	²²³Pa
92	²²⁷U	²²³U
93	²²⁸Np	²²³Np
94	²²⁹Pu
95	²³⁰Am	²²³Am

External data and identifiers

CAS:15623-45-7SMILES:[223Ra]PubChem:ID 6335825Adopted Levels, Gammas:NuDat 223Ra

Literature and References

[1] - T. Godlewski:
A New Radio-active Product from Actinium.
In: Nature, (1905), DOI 10.1038/071294b0.

[2] - D. N. Shishkin, S. V. Krupitskii, S. A. Kuznetsov:
Extraction generator of ²²³Ra for nuclear medicine.
In: Radiochemistry, (2011), DOI 10.1134/S1066362211040126.

[3] - Diane S. Abou, JuilePickett, John E. Mattson, Daniel L. J.Thorek:
A Radium-223 microgenerator from cyclotron-produced trace Actinium-227.
In: Applied Radiation and Isotopes, (2017), DOI 10.1016/j.apradiso.2016.10.015.