Boron-16

Properties and data of the isotope ¹⁶B.

Contents

Boron-16 is a radioisotope of the chemical element boron, which has 11 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 16. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁶B is exclusively for academic purposes.

The first report on the neutron-rich isotope dates back to 2000 [1]; according to this, boron-16 was produced by a multinucleon transfer reaction when carbon-14 was bombarded with a 336.6 MeV ¹⁴C beam:

¹⁴C(¹⁴C,¹²N)¹⁶B.

See also: List of individual Boron isotopes (and general data sources).

General data

Name of the isotope:Boron-16; B-16Symbol:¹⁶B or 165BMass number A:16 (= number of nucleons)Atomic number Z:5 (= number of protons)Neutrons N:11Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):2.2 (= neutron-proton ratio)Neutron excess (N-Z):6Isotopic mass:16.039841(26) u (atomic weight of Boron-16)Nuclide mass:16.0370981 u (calculated nuclear mass without electrons)Mass excess:37.11165 MeVMass defect:0.094598236 u (per nucleus)Nuclear binding energy:88.11768924 MeV (per nucleus)
5.50735558 MeV (average binding energy per nucleon)Separation energy:
S_P = 20.00(17) MeV (first proton)Half-life:> 4.6 × 10^-21 sDecay constant λ:1.506841696869 × 10⁺²⁰ s^-1Specific activity α:5.671508095108 × 10⁺⁴² Bq g^-1
1.532840025705 × 10⁺³² Ci g^-1Spin and parity:
(nuclear angular momentum)0-Year of discovery:2000

Radioactive Decay

For theoretical reasons, a radioactive decay with neutron emission to boron-15 is postulated for boron-16; this type of decay has not been observed experimentally. All information provided here is provisional.

Half-life T_½ = > 4.6 × 10^-21 s respectively 4.6 × 10^-21 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
n	¹⁵B	100 %

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 11) and isobaric (same nucleon number A = 16) with Boron-16. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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

External data and identifiers

Adopted Levels, Gammas:NuDat 16B

Literature and References

[1] - R. Kalpakchieva, H.G. Bohlen, W. von Oertzen et al.:
Spectroscopy of ¹³B, ¹⁴B, ¹⁵B and ¹⁶B using multi-nucleon transfer reactions.
In: The European Physical Journal A - Hadrons and Nuclei, 7, (2000), DOI 10.1007/PL00013641.