Boron-18

Properties and data of the isotope ¹⁸B.

Contents

Boron-18 is a radioisotope of the chemical element boron, which has 13 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 18. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁸B is exclusively for academic purposes.

An unbound state of boron-18 was first reported in 2010 [1]. The artificial generation of the nuclide was achieved by a one-proton knockout reaction when bombarding a beryllium target with a 62 MeV/u beam of carbon-19.

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

General data

Name of the isotope:Boron-18; B-18Symbol:¹⁸B or 185BMass number A:18 (= number of nucleons)Atomic number Z:5 (= number of protons)Neutrons N:13Isotopic mass:18.05560(22) u (atomic weight of Boron-18)Nuclide mass:18.0528571 u (calculated nuclear mass without electrons)Mass excess:51.79107 MeVMass defect:0.096169068000002 u (per nucleus)Nuclear binding energy:89.58090983 MeV (per nucleus)
4.97671721 MeV (average binding energy per nucleon)Half-life:< 26 nsDecay constant λ:26659506.944613 s^-1Specific activity α:8.919294782051 × 10⁺²⁹ Bq g^-1
2.410620211365 × 10⁺¹⁹ Ci g^-1Spin and parity:
(nuclear angular momentum)(2-)Year of discovery:2009

Radioactive Decay

Boron-18 decays radioactively with the emission of a neutron to boron-17.

Half-life T_½ = < 26 ns respectively 2.6 × 10^-8 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
n	¹⁷B

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 13) and isobaric (same nucleon number A = 18) with Boron-18. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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