Monoisotopic elements are the 26 chemical elements that only have a single stable isotope (nuclide); These are the following basic materials:
The term is not used consistently in the literature; In particular, the terms monoisotopic and mononuclide elements were previously used synonymously.
In its technical report on atomic weights, IUPAC defines the monoisotopic elements as follows:
An element is considered monoisotopic if it has one and only one isotope that is either stable or has a half-life greater than 1 × 1010 years [1].
| Element | Z (p) | N (n) | A | Isotop | Masse in u |
|---|---|---|---|---|---|
| Beryllium | 4 | 5 | 9 | 9Be | 9,0121831(5) |
| Fluorine | 9 | 10 | 19 | 19F | 18,998403163(6) |
| Sodium | 11 | 12 | 23 | 23Na | 22,98976928(2) |
| Aluminium | 13 | 14 | 27 | 27Al | 26,9815384(3) |
| Phosphorus | 15 | 16 | 31 | 31P | 30,973761998(5) |
| Scandium | 21 | 24 | 45 | 45Sc | 44,955907(4) |
| Vanadium | 23 | 28 | 51 | 51V | 50,9415(1) |
| Manganese | 25 | 30 | 55 | 55Mn | 54,938043(2) |
| Cobalt | 27 | 32 | 59 | 59Co | 58,933194(3) |
| Arsenic | 33 | 42 | 75 | 75As | 74,921595(6) |
| Rubidium | 37 | 48 | 85 | 85Rb | 85,4678(3) |
| Yttrium | 39 | 50 | 89 | 89Y | 88,90584(1) |
| Niobium | 41 | 52 | 93 | 93Nb | 92,90637(1) |
| Rhodium | 45 | 58 | 103 | 103Rh | 102,90549(2) |
| Indium | 49 | 64 | 113 | 113In | 114,818(1) |
| Iodine | 53 | 74 | 127 | 127I | 126,90447(3) |
| Cesium | 55 | 78 | 133 | 133Cs | 132,90545196(6) |
| Lanthanum | 57 | 82 | 139 | 139La | 138,90547(7) |
| Praseodymium | 59 | 82 | 141 | 141Pr | 140,90766(1) |
| Europium | 63 | 90 | 153 | 153Eu | 151,964(1) |
| Terbium | 65 | 94 | 159 | 159Tb | 158,925354(8) |
| Holmium | 67 | 98 | 165 | 165Ho | 164,930328(7) |
| Thulium | 69 | 100 | 169 | 169Tm | 168,934218(6) |
| Lutetium | 71 | 104 | 175 | 175Lu | 174,9668(1) |
| Rhenium | 75 | 110 | 185 | 185Re | 186,207(1) |
| Gold | 79 | 118 | 197 | 197Au | 196,966569(5) |
[1] - John R. de Laeter et al.:
Atomic weights of the elements. Review 2000 (IUPAC Technical Report).
In: Pure and Applied Chemistry, 75, 6, (2009), DOI 10.1351/pac200375060683.
[2] - N. E. Holden:
2013 Review of Neutron and Non-Neutron Nuclear Data.
EPJ Web of Conferences, (2016), DOI 10.1051/epjconf/201610604003.
Last update: 2025-12-28
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