Isotopes of tellurium

From Wikipedia, the free encyclopedia
  (Redirected from Tellurium-125)
Jump to: navigation, search

There are 38 known isotopes and 17 nuclear isomers of tellurium (Te) with atomic masses that range from 105 to 142. These are listed in the table below.

Naturally occurring tellurium on Earth consists of eight isotopes. Two of these have been found to be radioactive: 128Te and 130Te undergo double beta decay with half-lives of, respectively, 2.2×1024 (2.2 septillion) years (the longest half-life of all nuclides proven to be radioactive)[1] and 7.9×1020 (790 quintillion) years. The longest-lived artificial radioisotope is 121Te with a half-life of nearly 19 days. Several isomers have longer half-lives, the longest being 121mTe with a half-life of 154 days.

The very-long-lived radioisotopes 128Te and 130Te are the two most common isotopes of tellurium. Of elements with at least one stable isotope, only indium and rhenium likewise have a radioisotope in greater abundance than a stable one.

It has been claimed that electron capture of 123Te was observed, but the recent measurements of the same team have disproved this.[2] Tellurium-123's half life is longer than 9.2 × 1016 years, and probably much longer.[3]

124Te can be used as a starting material in the production of radionuclides by a cyclotron or other particle accelerators. Some common radionuclides that can be produced from tellurium-124 are iodine-123 and iodine-124.

The short-lived isotope 135Te (half-life 19 seconds) is produced as a fission product in nuclear reactors. It decays, via two beta decays, to 135Xe, the most powerful known neutron absorber, and the cause of the iodine pit phenomenon.

Tellurium is the lightest element observed to commonly undergo alpha decay, with isotopes 106Te to 110Te being seen to undergo this mode of decay; some lighter elements have isotopes with alpha decay as a rare branch.

Tellurium's standard atomic mass is: 127.60(3) u.

Table[edit]

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life[n 1] decay
mode(s)[4][n 2]
daughter
isotope(s)[n 3]
nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
105Te 52 53 104.94364(54)# 1 µs# 5/2+#
106Te 52 54 105.93750(14) 70(20) µs
[70(+20-10) µs]
α 102Sn 0+
107Te 52 55 106.93501(32)# 3.1(1) ms α (70%) 103Sn 5/2+#
β+ (30%) 107Sb
108Te 52 56 107.92944(11) 2.1(1) s β+ (51%) 108Sb 0+
α (49%) 104Sn
β+, p (2.4%) 107Sn
β+, α (.065%) 104In
109Te 52 57 108.92742(7) 4.6(3) s β+ (86.99%) 109Sb (5/2+)
β+, p (9.4%) 108Sn
α (7.9%) 105Sn
β+, α (.005%) 105In
110Te 52 58 109.92241(6) 18.6(8) s β+ (99.99%) 110Sb 0+
β+, p (.003%) 109Sn
111Te 52 59 110.92111(8) 19.3(4) s β+ 111Sb (5/2)+#
β+, p (rare) 110Sn
112Te 52 60 111.91701(18) 2.0(2) min β+ 112Sb 0+
113Te 52 61 112.91589(3) 1.7(2) min β+ 113Sb (7/2+)
114Te 52 62 113.91209(3) 15.2(7) min β+ 114Sb 0+
115Te 52 63 114.91190(3) 5.8(2) min β+ 115Sb 7/2+
115m1Te 10(7) keV 6.7(4) min β+ 115Sb (1/2)+
IT 115Te
115m2Te 280.05(20) keV 7.5(2) µs 11/2-
116Te 52 64 115.90846(3) 2.49(4) h β+ 116Sb 0+
117Te 52 65 116.908645(14) 62(2) min β+ 117Sb 1/2+
117mTe 296.1(5) keV 103(3) ms IT 117Te (11/2-)
118Te 52 66 117.905828(16) 6.00(2) d EC 118Sb 0+
119Te 52 67 118.906404(9) 16.05(5) h β+ 119Sb 1/2+
119mTe 260.96(5) keV 4.70(4) d β+ (99.99%) 119Sb 11/2-
IT (.008%) 119Te
120Te 52 68 119.90402(1) Observationally Stable[n 4] 0+ 9(1)×10−4
121Te 52 69 120.904936(28) 19.16(5) d β+ 121Sb 1/2+
121mTe 293.991(22) keV 154(7) d IT (88.6%) 121Te 11/2-
β+ (11.4%) 121Sb
122Te 52 70 121.9030439(16) Stable[n 5] 0+ 0.0255(12)
123Te 52 71 122.9042700(16) Observationally Stable[n 6] 1/2+ 0.0089(3)
123mTe 247.47(4) keV 119.2(1) d IT 123Te 11/2-
124Te 52 72 123.9028179(16) Stable[n 5] 0+ 0.0474(14)
125Te[n 7] 52 73 124.9044307(16) Stable[n 5] 1/2+ 0.0707(15)
125mTe 144.772(9) keV 57.40(15) d IT 125Te 11/2-
126Te 52 74 125.9033117(16) Stable[n 5] 0+ 0.1884(25)
127Te[n 7] 52 75 126.9052263(16) 9.35(7) h β- 127I 3/2+
127mTe 88.26(8) keV 109(2) d IT (97.6%) 127Te 11/2-
β- (2.4%) 127I
128Te[n 7][n 8] 52 76 127.9044631(19) 2.2(3)×1024 a[n 9] β-β- 128Xe 0+ 0.3174(8)
128mTe 2790.7(4) keV 370(30) ns 10+
129Te[n 7] 52 77 128.9065982(19) 69.6(3) min β- 129I 3/2+
129mTe 105.50(5) keV 33.6(1) d 11/2-
130Te[n 7][n 8] 52 78 129.9062244(21) 790(100)×1018 a β-β- 130Xe 0+ 0.3408(62)
130m1Te 2146.41(4) keV 115(8) ns (7)-
130m2Te 2661(7) keV 1.90(8) µs (10+)
130m3Te 4375.4(18) keV 261(33) ns
131Te[n 7] 52 79 130.9085239(21) 25.0(1) min β- 131I 3/2+
131mTe 182.250(20) keV 30(2) h β- (77.8%) 131I 11/2-
IT (22.2%) 131Te
132Te[n 7] 52 80 131.908553(7) 3.204(13) d β- 132I 0+
133Te 52 81 132.910955(26) 12.5(3) min β- 133I (3/2+)
133mTe 334.26(4) keV 55.4(4) min β- (82.5%) 133I (11/2-)
IT (17.5%) 133Te
134Te 52 82 133.911369(11) 41.8(8) min β- 134I 0+
134mTe 1691.34(16) keV 164.1(9) ns 6+
135Te[n 10] 52 83 134.91645(10) 19.0(2) s β- 135I (7/2-)
135mTe 1554.88(17) keV 510(20) ns (19/2-)
136Te 52 84 135.92010(5) 17.63(8) s β- (98.7%) 136I 0+
β-, n (1.3%) 135I
137Te 52 85 136.92532(13) 2.49(5) s β- (97.01%) 137I 3/2-#
β-, n (2.99%) 136I
138Te 52 86 137.92922(22)# 1.4(4) s β- (93.7%) 138I 0+
β-, n (6.3%) 137I
139Te 52 87 138.93473(43)# 500 ms
[>300 ns]#
β- 139I 5/2-#
β-, n 138I
140Te 52 88 139.93885(32)# 300 ms
[>300 ns]#
β- 140I 0+
β-, n 139I
141Te 52 89 140.94465(43)# 100 ms
[>300 ns]#
β- 141I 5/2-#
β-, n 140I
142Te 52 90 141.94908(64)# 50 ms
[>300 ns]#
β- 142I 0+
  1. ^ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
  2. ^ Abbreviations:
    EC: Electron capture
    IT: Isomeric transition
  3. ^ Bold for stable isotopes
  4. ^ Believed to undergo β+β+ decay to 120Sn with a half-life over 2.2×1016 years
  5. ^ a b c d Theoretically capable of spontaneous fission
  6. ^ Believed to undergo β+ decay to 123Sb with a half-life over 9.2×1016 years
  7. ^ a b c d e f g Fission product
  8. ^ a b Primordial radionuclide
  9. ^ Longest measured half-life of any nuclide
  10. ^ Very short-lived fission product, responsible for the iodine pit as precursor of 135Xe via 135I

Notes[edit]

  • Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References[edit]

  1. ^ Many isotopes are expected to have longer half-lives, but decay has not yet been observed in these, allowing only a lower limit to be placed on their half-lives
  2. ^ A. Alessandrello et al. New Limits on Naturally Occurring Electron Capture of 123Te. Phys. Rev. C 67 (2003) 014323.
  3. ^ New Limits on Naturally Occurring Electron Capture of 123Te full paper on arXiv URL: [1] DOI: 10.1103/PhysRevC.67.014323.
  4. ^ http://www.nucleonica.net/unc.aspx


Isotopes of antimony Isotopes of tellurium Isotopes of iodine
Table of nuclides