Boron-19

Properties and data of the isotope ¹⁹B.

Contents

Boron-19 is a radioisotope of the chemical element boron, which has 14 neutrons in its atomic nucleus in addition to the element-specific 5 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 19. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁹B is exclusively for academic purposes.

The discovery of the neutron-rich nuclide was reported in 1984 [1]. It was artificially produced by irradiating beryllium with a beam of accelerated iron-56 nuclei.

General data

Name of the isotope:Boron-19; B-19Symbol:¹⁹B or 195BMass number A:19 (= number of nucleons)Atomic number Z:5 (= number of protons)Neutrons N:14Isotopic mass:19.06417(56) u (atomic weight of Boron-19)Nuclide mass:19.0614271 u (calculated nuclear mass without electrons)Mass excess:59.77397 MeVMass defect:0.096263984 u (per nucleus)Nuclear binding energy:89.66932351 MeV (per nucleus)
4.71943808 MeV (average binding energy per nucleon)Separation energy:S_N = 0.094(564) MeV (first neutron)Half-life:2.92(13) msDecay constant λ:237.37917142464 s^-1Specific activity α:7.523846355443 × 10⁺²⁴ Bq g^-1
2.033471987957 × 10⁺¹⁴ Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Year of discovery:1984

Radioactive Decay

Half-life T_½ = 2.92(13) ms respectively 2.92 × 10^-3 seconds s.

Decay mode	Daughter	Probability
β^-, n	¹⁸C	71 %
β^-, 2n	¹⁷C	17 %
β^-	¹⁹C	> 2.9 %
β^-, 3n	¹⁶C	< 9.1 %

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 14) and isobaric (same nucleon number A = 19) with Boron-19. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 14	Isobar A = 19
5	¹⁹B	¹⁹B
6	²⁰C	¹⁹C
7	²¹N	¹⁹N
8	²²O	¹⁹O
9	²³F	¹⁹F
10	²⁴Ne	¹⁹Ne
11	²⁵Na	¹⁹Na
12	²⁶Mg	¹⁹Mg
13	²⁷Al
14	²⁸Si
15	²⁹P
16	³⁰S
17	³¹Cl
18	³²Ar
19	³³K
20	³⁴Ca

External data and identifiers

Adopted Levels, Gammas:NuDat 19B

Literature and References

[1] - J. A. Musser, J. D. Stevenson:
First Observation of the Neutron-Rich Isotope ¹⁹B.
In: Physical Review Letters, 53, 2544, (1984), DOI 10.1103/PhysRevLett.53.2544.

[2] - J. Casal, E. Garrido:
Three-body structure of ¹⁹B: Finite-range effects in two-neutron halo nuclei.
In: Physical Review C, 102, 051304(R), (2020), DOI 10.1103/PhysRevC.102.051304.