Isotopes of germanium

Germanium isotopes are mainly used for the production of medical As and Se radioisotopes. Ge-74 is used for the production of As-74, Ge-76 for the production of As-77, Ge-74 for the production of As-73 and Ge-72 for As-72. Ge-70, Ge-72 and Ge-74 can all be used for the production of the medical radioisotope Se-73, although the most common production route is via natural As (As-75). Natural GeF4 is used in the semiconductor pre-amorphisation implant process. The use of Ge-72, in the form of GeF4, improves this process and reduces contamination. Finally, Ge-76 is used to study double beta decay. Germanium isotopes can be obtained from Trace Sciences International.

Naturally occurring isotopes

This table shows information about naturally occuring isotopes, their atomic masses, their natural abundances, their nuclear spins, and their magnetic moments. Further data for radioisotopes (radioactive isotopes) of germanium are listed (including any which occur naturally) below.
Isotope Atomic mass (ma/u) Natural abundance (atom %) Nuclear spin (I) Magnetic moment (μ/μN)
70Ge 69.9242497 (16) 20.84 (87) 0
72Ge 71.9220789 (16) 27.54 (34) 0
73Ge 72.9234626 (16) 7.73 (5) 9/2 -0.8794669
74Ge 73.9211774 (15) 36.28 (73) 0
76Ge 75.9214016 (17) 7.61 (38) 0

Isotopic abundances of Ge
In the above picture, the most intense ion is set to 100% since this corresponds best to the output from a mass spectrometer. This is not to be confused with the relative percentage isotope abundances which total 100% for all the naturally occurring isotopes.

Radiosotope data

Further data for naturally occuring isotopes of germanium are listed above. This table gives information about some radiosotopes of germanium, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments.
Isotope Mass Half-life Mode of decay Nuclear spin Nuclear magnetic moment
64Ge 63.9416 1.06 m EC to 64Ga 0
65Ge 64.9394 31 s EC to 65Ga
66Ge 65.93385 2.26 h EC to 66Ga 0
67Ge 66.932738 19.0 m EC to 67Ga 1/2
68Ge 67.92810 270.8 d EC to 68Ga 0
69Ge 68.927973 1.63 d EC to 69Ga 5/2 0.735
71Ge 70.924954 11.2 d EC to 71Ga 1/2 0.547
75Ge 74.922860 1.380 h β- to 75As 1/2 0.510
77Ge 76.923549 11.30 h β- to 77As 7/2
78Ge 77.922853 1.45 h β- to 78As 0

Sheffield ChemPuter isotope pattern calculator

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References

  1. Naturally occurring isotope abundances: Commission on Atomic Weights and Isotopic Abundances report for the International Union of Pure and Applied Chemistry in Isotopic Compositions of the Elements 1989, Pure and Applied Chemistry, 1998, 70, 217. [Copyright 1998 IUPAC]
  2. For further information about radioisotopes see Jonghwa Chang's (Korea Atomic Energy Research Institute) Table of the Nuclides
  3. Masses, nuclear spins, and magnetic moments: I. Mills, T. Cvitas, K. Homann, N. Kallay, and K. Kuchitsu in Quantities, Units and Symbols in Physical Chemistry, Blackwell Scientific Publications, Oxford, UK, 1988. [Copyright 1988 IUPAC]

NMR Properties of germanium

Common reference compound: Ge(CH3)4 + 10% C6D6.

Table of NMR-active nucleus propeties of germanium
  Isotope 1 Isotope 2 Isotope 3
Isotope 73Ge
Natural abundance /% 7.73
Spin (I) 9/2
Frequency relative to 1H = 100 (MHz) 3.488315
Receptivity, DP, relative to 1H = 1.00 0.000109
Receptivity, DC, relative to 13C = 1.00 0.624
Magnetogyric ratio, γ (107 rad T-1 s-1) -0.9360303
Magnetic moment, μ (μN) -0.9722881
Nuclear quadrupole moment, Q/millibarn -196
Line width factor, 1056l (m4) 0.0022

References

  1. R.K. Harris in Encyclopedia of Nuclear Magnetic Resonance, D.M. Granty and R.K. Harris, (eds.), vol. 5, John Wiley & Sons, Chichester, UK, 1996. I am grateful to Professor Robin Harris (University of Durham, UK) who provided much of the NMR data, which are copyright 1996 IUPAC, adapted from his contribution contained within this reference.
  2. J. Mason in Multinuclear NMR, Plenum Press, New York, USA, 1987. Where given, data for certain radioactive nuclei are from this reference.
  3. P. Pyykkö, Mol. Phys., 2008, 106, 1965-1974.
  4. P. Pyykkö, Mol. Phys., 2001, 99, 1617-1629.
  5. P. Pyykkö, Z. Naturforsch., 1992, 47a, 189. I am grateful to Professor Pekka Pyykkö (University of Helsinki, Finland) who provided the nuclear quadrupole moment data in this and the following two references.
  6. D.R. Lide, (ed.), CRC Handbook of Chemistry and Physics 1999-2000 : A Ready-Reference Book of Chemical and Physical Data (CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, Florida, USA, 79th edition, 1998.
  7. P. Pyykkö, personal communication, 1998, 204, 2008, 2010.
  8. The isotopic abundances are extracted from the naturally occurring isotopes section within WebElements.

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germanium atomic number