矽（原子量：28.0855(3)）共有23個已知同位素，質量數介於22-44之間，其中有3個是穩定的，其他都具有放射性。天然存在的矽同位素有5個，分別是穩定的28Si、29Si、30Si和具放射性的31Si及32Si，31Si及32Si在自然界中僅痕量存在，為宇宙射線散裂所產生。其餘同位素都不出現在自然界中，只有在實驗室製造出來過，且半衰期都極短，非常不穩定。
Quick Facts 同位素, 衰變 ...
主要的矽同位素|
|
| 標準原子質量 (Ar, 標準) | - [28.084, 28.086][1]
- 傳統: 28.085
|
|---|
|
|
|
Close
More information 符號, Z ...
| 符號
|
Z
|
N
|
同位素質量（u）[2]
[n 1][n 2]
|
半衰期
[n 1][n 2]
|
衰變
方式[3]
|
衰變
產物
[n 3]
|
原子核
自旋[n 1]
|
相對豐度
（莫耳分率）[n 2]
|
相對豐度
的變化量
（莫耳分率）
|
| 22Si
|
14
|
8
|
22.03611(54)#
|
29(2) ms
|
β+ (68%)
|
22Al
|
0+
|
|
|
| β+, p (32%)
|
21Mg
|
| 23Si
|
14
|
9
|
23.02571(54)#
|
42.3(4) ms
|
β+
|
23Al
|
3/2+#
|
|
|
| 24Si
|
14
|
10
|
24.011535(21)
|
140(8) ms
|
β+ (92%)
|
24Al
|
0+
|
|
|
| β+, p (8%)
|
23Mg
|
| 25Si
|
14
|
11
|
25.004109(11)
|
220(3) ms
|
β+ (63.19%)
|
25Al
|
5/2+
|
|
|
| β+, p (36.8%)
|
24Mg
|
| 26Si
|
14
|
12
|
25.99233382(12)
|
2.234(13) s
|
β+
|
26Al
|
0+
|
|
|
| 27Si
|
14
|
13
|
26.98670469(12)
|
4.16(2) s
|
β+
|
27Al
|
5/2+
|
|
|
| 28Si
|
14
|
14
|
27.9769265344(6)
|
穩定
|
0+
|
0.92223(19)
|
0.92205–0.92241
|
| 29Si
|
14
|
15
|
28.9764946643(6)
|
穩定
|
1/2+
|
0.04685(8)
|
0.04678–0.04692
|
| 30Si
|
14
|
16
|
29.973770137(23)
|
穩定
|
0+
|
0.03092(11)
|
0.03082–0.03102
|
| 31Si
|
14
|
17
|
30.97536320(5)
|
157.3(3) min
|
β−
|
31P
|
3/2+
|
|
|
| 32Si
|
14
|
18
|
31.9741515(3)
|
153(19) y
|
β−
|
32P
|
0+
|
痕量或天然放射性
|
宇宙成因
|
| 33Si
|
14
|
19
|
32.9779770(8)
|
6.18(18) s
|
β−
|
33P
|
(3/2+)
|
|
|
| 34Si
|
14
|
20
|
33.9785380(9)
|
2.77(20) s
|
β−
|
34P
|
0+
|
|
|
| 35Si
|
14
|
21
|
34.98455(4)
|
780(120) ms
|
β− (94.74%)
|
35P
|
7/2−#
|
|
|
| β−, n (5.26%)
|
34P
|
| 36Si
|
14
|
22
|
35.98665(8)
|
0.45(6) s
|
β− (88%)
|
36P
|
0+
|
|
|
| β−, n (12%)
|
35P
|
| 37Si
|
14
|
23
|
36.99295(12)
|
90(60) ms
|
β− (83%)
|
37P
|
(7/2−)#
|
|
|
| β−, n (17%)
|
36P
|
| 38Si
|
14
|
24
|
37.99552(11)
|
90# ms [>1 µs]
|
β−, n
|
37P
|
0+
|
|
|
| β−
|
38P
|
| 39Si
|
14
|
25
|
39.00249(15)
|
47.5(20) ms
|
β−
|
39P
|
7/2−#
|
|
|
| 40Si
|
14
|
26
|
40.00608(13)
|
33.0(10) ms
|
β−
|
40P
|
0+
|
|
|
| 41Si
|
14
|
27
|
41.01417(32)#
|
20.0(25) ms
|
β−
|
41P
|
7/2−#
|
|
|
| 42Si
|
14
|
28
|
42.01808(32)#
|
13(4) ms
|
β−
|
42P
|
0+
|
|
|
| 43Si
|
14
|
29
|
43.02612(43)#
|
15# ms [>260 ns]
|
|
|
3/2−#
|
|
|
| 44Si
|
14
|
30
|
44.03147(54)#
|
10# ms
|
|
|
0+
|
|
|
Close
畫上#號的數據代表沒有經過實驗的証明，僅為理論推測。
Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. The AME 2020 atomic mass evaluation (II). Tables, graphs and references. Chinese Physics C. 2021, 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
- Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report) （頁面存檔備份，存於網際網路檔案館）. Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005) （頁面存檔備份，存於網際網路檔案館）.
- Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties （頁面存檔備份，存於網際網路檔案館）, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database （頁面存檔備份，存於網際網路檔案館） (retrieved Sept. 2005).
- David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.
