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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 |
|
 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 |
|
References
- 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]
- 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]
- For further information about radioisotopes see Jonghwa Chang's (Korea Atomic Energy Research Institute) Table of the Nuclides
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