Silicon-26

Properties and data of the isotope ²⁶Si.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Silicon-26 is a radioisotope of the chemical element silicon, which has 12 neutrons in its atomic nucleus in addition to the element-specific 14 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 26. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²⁶Si is exclusively for academic purposes.

The first observation of the nuclide was reported in 1960 [1]; according to this, silicon-26 could be produced and identified by irradiating a magnesium-24 containing template with helium-3 ions of an energy of 8 MeV:

²⁴Mg(³He,n)²⁶Si.

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

General data

Name of the isotope:Silicon-26; Si-26Symbol:²⁶Si or 2614SiMass number A:26 (= number of nucleons)Atomic number Z:14 (= number of protons)Neutrons N:12Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):0.85714285714286 (= neutron-proton ratio)Neutron excess (N-Z):-2Isotopic mass:25.99233382(12) u (atomic weight of Silicon-26)Nuclide mass:25.9846538 u (calculated nuclear mass without electrons)Mass excess:-7.141 MeVMass defect:0.22119562 u (per nucleus)Nuclear binding energy:206.04239286 MeV (per nucleus)
7.92470742 MeV (average binding energy per nucleon)Separation energy:S_N = 19.040(10) MeV (first neutron)
S_P = 5.51400(11) MeV (first proton)Half-life:2.2453(7) sDecay constant λ:0.30871027504563 s^-1Specific activity α:7.436387044938 × 10⁺²¹ Bq g^-1
200983433646.98 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Isobaric spin: 1Mirror nucleus:Magnesium-26Year of discovery:1960

Radioactive Decay

Half-life T_½ = 2.2453(7) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	²⁶Al	100 %	5.06914(13) MeV

Parent Nuclides

Direct parent isotope is: ²⁶P.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 12) and isobaric (same nucleon number A = 26) with Silicon-26. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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