Isotope: Radium-201
General data
| Element name | Radium |
|---|---|
| Chemical symbol | Ra |
| Atomic number Z | 88 |
| Isotope name (symbol) | Radium-201 (Ra-201) |
| Neutron number N | 113 |
| Mass number A=Z+N | 201 |
Ground state
| Half-life | 10 +40/−0 ms |
|---|---|
| Spin / Parity | (3/2-) |
| Mass excess | 11937 ± 20 keV |
Decay branches
α 100%Isomers
| Isomer | Energy | Half-life | Spin / Parity | Decay branches |
|---|---|---|---|---|
| Isomer 1 | 260 ± 30 keV | 2 +8/−1 ms | (13/2+) | α 100% |
Produced by decay of
NNDC data contain no decay that leads to this isotope.
Many isotopes are also produced, often mainly, in nuclear reactions (e.g. Co-60 from Co-59 by neutron capture, C-14 from nitrogen-14 in the atmosphere) and in fission (e.g. Cs-137, I-131) - those routes are not listed here.
Radioactive decay series
- Radium-201 10 ms
- Radon-197 55 ms
- Polonium-193 410 ms
- Lead-189 39 s
- Thallium-189 2.3 min · 99.6%
- Mercury-189 8.0 min · 99.6%
- Gold-189 28.7 min · 99.6%
- Platinum-189 10.89 h · 99.6%
- Iridium-189 13.2 d · 99.6%
- Osmium-189 stable · 99.6%
- Mercury-185 48.2 s · 0.4%
- Gold-185 4.3 min · 0.37%
- Platinum-185 70.9 min · 0.37%
- Iridium-185 14.4 h · 0.37%
- Osmium-185 92.95 d · 0.37%
- Rhenium-185 stable · 0.37%
- Platinum-181 52.0 s · 0.024%
- Iridium-181 4.90 min · 0.025%
- Osmium-181 106 min · 0.025%
- Rhenium-181 20.0 h · 0.025%
- Tungsten-181 120.96 d · 0.025%
- Tantalum-181 stable · 0.025%
Rare branches (below 0.01%)
Rare branches are transformations that occur in fewer than 0.01% of decays, e.g. double beta decay or cluster emission. The nuclides they produce are practically absent from a sample, so they are hidden by default to keep the main path clear. In this series: branches - 1, nuclides - 5.
- Osmium-177 3.0 min · 1.8×10⁻⁵%
- Rhenium-177 14 min · 1.8×10⁻⁵%
- Tungsten-177 132 min · 1.8×10⁻⁵%
- Tantalum-177 56.56 h · 1.8×10⁻⁵%
- Hafnium-177 stable · 1.8×10⁻⁵%
Decay notation
| Notation | Name | On the chart | Description |
|---|---|---|---|
| α | alpha decay | Alpha decay is the emission of a helium nucleus (2 protons + 2 neutrons): Z−2, A−4. | |
| β⁻, 2β⁻ | beta-minus decay | In beta-minus decay a neutron turns into a proton and the nucleus emits an electron: Z+1, A unchanged. 2β⁻ is double beta decay. | |
| EC, EC/β⁺ | electron capture / beta-plus decay | A proton turns into a neutron: the nucleus captures a shell electron (EC) or emits a positron (β⁺): Z−1, A unchanged. | |
| p, 2p, 3p | proton emission | Proton emission is the ejection of a proton from the nucleus: Z−1, A−1. 2p, 3p - two, three protons. | |
| n, 2n…4n | neutron emission | Neutron emission is the ejection of a neutron from the nucleus: A−1, Z unchanged. 2n…4n - several neutrons. | |
| ¹⁴C, ²⁴Ne… | cluster emission | Cluster emission is the ejection of a light nucleus, e.g. ¹⁴C, ²⁰O, ²⁴Ne, ²⁸Mg, ³⁴Si. It is a very rare transformation. | |
| IT | isomeric transition | An isomeric transition takes a nucleus from an excited state (an isomer, e.g. Pa-234m) to the ground state, usually emitting a γ photon: Z and A unchanged. | |
| β⁻n, ECp, ECα… | delayed emission | Delayed emission is the emission of a particle (n, p or α) right after β⁻ decay or electron capture. The arrow has the colour of the emitted particle and its label shows the transformation, e.g. “β⁻n 63%”. | |
| SF | spontaneous fission | no arrow | Spontaneous fission is the splitting of a nucleus into two fragments of random masses. There is no single daughter, so the chart shows no arrow - it is listed in the decay branches and in the tile tooltip. |
Data sources
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain