Silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ...

(₁₄Si) has 23 known

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass num ...

s, with

mass number The mass number (symbol ''A'', from the German word ''Atomgewicht'' tomic weight, also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approxima ...

s ranging from 22 to 44. ²⁸Si (the most abundant isotope, at 92.23%), ²⁹Si (4.67%), and ³⁰Si (3.1%) are stable. The longest-lived radioisotope is ³²Si, which is produced by

cosmic ray spallation Cosmic ray spallation, also known as the x-process, is a set of naturally occurring nuclear reactions causing nucleosynthesis; it refers to the formation of chemical elements from the impact of cosmic rays on an object. Cosmic rays are highly ener ...

argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice a ...

. Its

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ...

has been determined to be approximately 150 years (with

decay energy The decay energy is the energy change of a nucleus having undergone a radioactive decay. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation. This decay, or loss of energy ...

0.21 MeV), and it decays by

beta emission In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For exam ...

to ³² P (which has a 14.28-day half-life) and then to ³² S. After ³²Si, ³¹Si has the second longest half-life at 157.3 minutes. All others have half-lives under 7 seconds.

List of isotopes

, - , rowspan=2, ²²Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 8 , rowspan=2, 22.03579(54)# , rowspan=2, 29(2) ms , β⁺ (67.6%) , ²²Al , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p (32.4%) , ²¹Mg , - , rowspan=2, ²³Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 9 , rowspan=2, 23.02544(54)# , rowspan=2, 42.3(4) ms , β⁺, p (88%) , ²²Mg , rowspan=2, 3/2+# , rowspan=2, , rowspan=2, , - , β⁺ (12%) , ²³Al , - , rowspan=2, ²⁴Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 10 , rowspan=2, 24.011535(21) , rowspan=2, 140(8) ms , β⁺ (62.4%) , ²⁴Al , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p (37.6%) , ²³Mg , - , rowspan=2, ²⁵Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 11 , rowspan=2, 25.004109(11) , rowspan=2, 220(3) ms , β⁺ (64.8%) , ²⁵Al , rowspan=2, 5/2+ , rowspan=2, , rowspan=2, , - , β⁺, p (35.2%) , ²⁴Mg , - , ²⁶Si , style="text-align:right" , 14 , style="text-align:right" , 12 , 25.9923338(12) , 2.2453(7) s , β⁺ , ²⁶Al , 0+ , , , - , ²⁷Si , style="text-align:right" , 14 , style="text-align:right" , 13 , 26.98670469(12) , 4.15(4) s , β⁺ , ²⁷Al , 5/2+ , , , - , ²⁸Si , style="text-align:right" , 14 , style="text-align:right" , 14 , 27.9769265350(5) , colspan=3 align=center, Stable , 0+ , 0.92223(19) , 0.92205–0.92241 , - , ²⁹Si , style="text-align:right" , 14 , style="text-align:right" , 15 , 28.9764946653(6) , colspan=3 align=center, Stable , 1/2+ , 0.04685(8) , 0.04678–0.04692 , - , ³⁰Si , style="text-align:right" , 14 , style="text-align:right" , 16 , 29.973770137(23) , colspan=3 align=center, Stable , 0+ , 0.03092(11) , 0.03082–0.03102 , - , ³¹Si , style="text-align:right" , 14 , style="text-align:right" , 17 , 30.97536319(5) , 157.36(26) min , β⁻ , ³¹P , 3/2+ , , , - , ³²Si , style="text-align:right" , 14 , style="text-align:right" , 18 , 31.9741515(3) , 153(19) y , β⁻ , ³²P , 0+ , trace ,

cosmogenic Cosmogenic nuclides (or cosmogenic isotopes) are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an ''in situ'' Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom ...

, - , ³³Si , style="text-align:right" , 14 , style="text-align:right" , 19 , 32.9779770(8) , 6.18(18) s , β⁻ , ³³P , (3/2+) , , , - , ³⁴Si , style="text-align:right" , 14 , style="text-align:right" , 20 , 33.978575(15) , 2.77(20) s , β⁻ , ³⁴P , 0+ , , , - , style="text-indent:1em" , ^34mSi , colspan=3 style="text-indent:2em" , 4256.1(4) keV , <210 ns , IT , ³⁴Si , (3−) , , , - , ³⁵Si , style="text-align:right" , 14 , style="text-align:right" , 21 , 34.98455(4) , 780(120) ms , β⁻ (94.74%) , ³⁵P , 7/2−# , , , - , rowspan=2, ³⁶Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 22 , rowspan=2, 35.98665(8) , rowspan=2, 450(60) ms , β⁻ (87.5%) , ³⁶P , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n (12.5%) , ³⁵P , - , rowspan=2, ³⁷Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 23 , rowspan=2, 36.99295(12) , rowspan=2, 90(60) ms , β⁻ (83%) , ³⁷P , rowspan=2, (7/2−)# , rowspan=2, , rowspan=2, , - , β⁻, n (17%) , ³⁶P , - , rowspan=2, ³⁸Si , rowspan=2 style="text-align:right" , 14 , rowspan=2 style="text-align:right" , 24 , rowspan=2, 37.99552(11) , rowspan=2, 90# ms 1 μs, β⁻, n , ³⁷P , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻ , ³⁸P , - , ³⁹Si , style="text-align:right" , 14 , style="text-align:right" , 25 , 39.00249(15) , 47.5(20) ms , β⁻ , ³⁹P , 7/2−# , , , - , ⁴⁰Si , style="text-align:right" , 14 , style="text-align:right" , 26 , 40.00583(37) , 33.0(10) ms , β⁻ , ⁴⁰P , 0+ , , , - , ⁴¹Si , style="text-align:right" , 14 , style="text-align:right" , 27 , 41.01301(60) , 20.0(25) ms , β⁻ , ⁴¹P , 7/2−# , , , - , ⁴²Si , style="text-align:right" , 14 , style="text-align:right" , 28 , 42.01768(54)# , 12.5(35) ms , β⁻ , ⁴²P , 0+ , , , - , ⁴³Si , style="text-align:right" , 14 , style="text-align:right" , 29 , 43.02480(64)# , 15# ms 260 ns, , , 3/2−# , , , - , ⁴⁴Si , style="text-align:right" , 14 , style="text-align:right" , 30 , 44.03147(54)# , 4# ms 360 ns, , , 0+ , , , - , ⁴⁵Si?The existence of this isotope has not been confirmed experimentally; given data is inferred or estimated from periodic trends. , style="text-align:right" , 14 , style="text-align:right" , 31 , 45.03982(64)# , 4# ms , , , 3/2−# , ,

References

External links

Silicon isotopes data from ''The Berkeley Laboratory Isotopes Project's''
{{Navbox element isotopes Silicon