Copper-64

Properties and data of the isotope ⁶⁴Cu.

Contents

General Data

Radioactive Decay

Isotones und Isobares

Literature

Copper-64 is a radioisotope of the chemical element copper. The atomic nucleus of the nuclide ⁶⁴Cu consists of the element-specific 29 protons and 35 neutrons; the mass number 64 results from the sum of these nucleons.

In practice, ⁶⁴Cu is used as a medical radionuclide (see below) - there are no practical technical applications.

The discovery of the radioactive nuclide during the irradiation of natural Cu templates with deuterons (hydrogen-2 nuclei) was reported in 1936 [1].

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

General data

Name of the isotope:Copper-64; Cu-64Symbol:⁶⁴Cu or 6429CuMass number A:64 (= number of nucleons)Atomic number Z:29 (= number of protons)Neutrons N:35Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.2068965517241 (= neutron-proton ratio)Neutron excess (N-Z):6Isotopic mass:63.9297640(5) u (atomic weight of Copper-64)Nuclide mass:63.9138556 u (calculated nuclear mass without electrons)Mass excess:-65.42441 MeVMass defect:0.600433988 u (per nucleus)Nuclear binding energy:559.30065722 MeV (per nucleus)
8.73907277 MeV (average binding energy per nucleon)Separation energy:S_N = 7.915868(24) MeV (first neutron)
S_P = 7.200498(28) MeV (first proton)Half-life:12.7006(20) hDecay constant λ:1.515998326763 × 10^-5 s^-1Specific activity α:1.449135788443 × 10⁺¹⁷ Bq g^-1
3916583.2120103 Ci g^-1Spin and parity:
(nuclear angular momentum)1+Magnetic dipole moment:μ(μ_N) = -0.2166(4)Year of discovery:1936

Radioactive Decay

Copper-64 decays radioactively via three modes including positron emission (17.52% β⁺), electron emission (38.5% β^–; Auger electrons) and electron capture (44.0% EE).

Half-life T_½ = 12.7006(20) h (hours) respectively 4.572216 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	Details	γ energy (intensity)
β^-	⁶⁴Zn	38.48(26) %	0.5796(6) MeV		1.346 MeV (0.472(4) %)
ε	⁶⁴Ni	61.52(26) %	1.6746(6) MeV	β⁺: 17.52 % (652.62 keV) EE: 44.0 %

Parent Nuclides

Direct parent isotopes are: ⁶⁴Zn, ⁶⁴Ni.

Formation

Copper-64 does not occur naturally and must be produced artificially; several processes are available for this, which are carried out in nuclear power plants or a biomedical cyclotron. Starting materials include the stable natural and possibly enriched isotopes nickel-64, zinc-64 and copper-63. The corresponding reactions are:

⁶⁴Ni(p,n)⁶⁴Cu
Cyclotron; currently the most common method. The specific activity of ⁶⁴Cu is between 47.4 and 474 GBq/μmol (1280 and 12800 mCi/μmol).
⁶⁴Ni(d,2n)⁶⁴Cu: cyclotron.
⁶⁴Zn(n,p)⁶⁴Cu: nuclear reactor.
⁶³Cu(n,γ)⁶⁴Cu: Nuclear reactor.
⁶⁵Cu(p,pn)⁶⁴Cu [4]
⁶⁷Zn(p,α)⁶⁴Cu [4]

A more recent method employs so-called recoil chemistry: zinc-64 or copper-63 are reacted with suitable molecules to form a soluble organometallic complex prior to irradiation, which is then irradiated with neutrons. The nuclear reactions ⁶⁴Zn(n,p)⁶⁴Cu or ⁶³Cu(n,γ;)⁶⁴Cu (support-free) produce copper-64, which emits a photon due to its increased energy; the recoil then allows it to be ejected from the molecule. Separation is achieved by liquid-liquid extraction [5].

Copper-64 as a Radionuclide in Medicine

Due to its radiation properties in combination with its short half-life, copper-64 is a medical radionuclide that is suitable for both positron emission tomography (⁶⁴Cu-PET) and for cancer radiation therapy (theranostic).

Substance monographs are available for the following ⁶⁴Cu radiopharmaceuticals:

- Copper dotatate Cu-64.

NMR data

Nuclear magnetic properties and parameters of the NMR active Nuclide ⁶⁴Cu

Isotope:⁶⁴Cu-NMRQuantity:Does not occur in nature!Spin:1+Nuclearmagnetic moment
μ/μ_N:-0.2166(4)Nuclear g-factor:g_l = -0.2166Quadrupole moment Q:0.075(9) barn (100 fm²)Line width parameter (factor):l = 281.25 fm⁴

The copper-64 nucleus is basically suitable for NMR spectroscopy.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 35) and isobaric (same nucleon number A = 64) with Copper-64. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 35	Isobar A = 64
17	⁵²Cl
18	⁵³Ar
19	⁵⁴K
20	⁵⁵Ca
21	⁵⁶Sc
22	⁵⁷Ti	⁶⁴Ti
23	⁵⁸V	⁶⁴V
24	⁵⁹Cr	⁶⁴Cr
25	⁶⁰Mn	⁶⁴Mn
26	⁶¹Fe	⁶⁴Fe
27	⁶²Co	⁶⁴Co
28	⁶³Ni	⁶⁴Ni
29	⁶⁴Cu	⁶⁴Cu
30	⁶⁵Zn	⁶⁴Zn
31	⁶⁶Ga	⁶⁴Ga
32	⁶⁷Ge	⁶⁴Ge
33	⁶⁸As	⁶⁴As
34	⁶⁹Se	⁶⁴Se
35	⁷⁰Br
36	⁷¹Kr
37	⁷²Rb
38	⁷³Sr

External data and identifiers

CAS:13981-25-4InChI Key:RYGMFSIKBFXOCR-IGMARMGPSA-NSMILES:[64Cu]PubChem:ID 105141Adopted Levels, Gammas:NuDat 64Cu

Literature and References

[0] - Research articles in scientific journals via PubMed: Copper-64.

[1] - S. N. van Voorhis:
The Artificial Radioactivity of Copper, a Branch Reaction.
In: Physical Review, 50, 895, (1936), DOI 10.1103/PhysRev.50.895.

[2] - Yeye Zhou et al.:
⁶⁴Cu-based Radiopharmaceuticals in Molecular Imaging.
In: Technology in Cancer Research & Treatment, (2019), DOI 10.1177/1533033819830.

[3] - Olga O. Krasnovskaya et al.:
Recent Advances in ⁶⁴Cu/⁶⁷Cu-Based Radiopharmaceuticals.
In: International Journal of Molecular Sciences, 24(11):9154, (2023), DOI 10.3390/ijms24119154.

[4] - Gaia Dellepiane, Pierluigi Casolaro, Isidre Mateu, Paola Scampoli , Saverio Braccini:
Alternative routes for 64Cu production using an 18 MeV medical cyclotron in view of theranostic applications.
In: Applied Radiation and Isotopes, 191, 110518, (2023), DOI 10.1016/j.apradiso.2022.110518.

[5] - Martin Pressler, Christoph Denk, Hannes Mikula, Veronika Rosecker:
Fast and easy reactor-based production of copper-64 with high molar activities using recoil chemistry.
In: Dalton Transactions, 54, (2025), DOI 10.1039/D5DT02046H.