Isotopes of hafnium

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Natural hafnium (Hf) consists of five stable isotopes (176Hf, 177Hf, 178Hf, 179Hf, and 180Hf) and one very long-lived radioisotope, 174Hf, with a half-life of 2×1015 years. In addition, there are 30 other known radionuclides, the most stable of which is 182Hf with a half-life of 8.9×106 years. No other radioisotope has a half-life over 1.87 days. Most isotopes have half-lives under 1 minute. There are also 27 known nuclear isomers, the most stable of which is 178m2Hf with a half-life of 31 years.

Standard atomic mass: 178.49(2) u

Table[edit]

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life[n 1] decay
mode(s)[1][n 2]
daughter
isotope(s)[n 3]
nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
153Hf 72 81 152.97069(54)# 400# ms [>200 ns] 1/2+#
153mHf 750(100)# keV 500# ms 11/2-#
154Hf 72 82 153.96486(54)# 2(1) sec β+ 154Lu 0+
α (rare) 150Yb
155Hf 72 83 154.96339(43)# 890(120) ms β+ 155Lu 7/2-#
α (rare) 151Yb
156Hf 72 84 155.95936(22) 23(1) ms α (97%) 152Yb 0+
β+ (3%) 156Lu
156mHf 1959.0(10) keV 480(40) µs 8+
157Hf 72 85 156.95840(21)# 115(1) ms α (86%) 153Yb 7/2-
β+ (14%) 157Lu
158Hf 72 86 157.954799(19) 2.84(7) sec β+ (55%) 158Lu 0+
α (45%) 154Yb
159Hf 72 87 158.953995(18) 5.20(10) sec β+ (59%) 159Lu 7/2-#
α (41%) 155Yb
160Hf 72 88 159.950684(12) 13.6(2) sec β+ (99.3%) 160Lu 0+
α (.7%) 156Yb
161Hf 72 89 160.950275(24) 18.2(5) sec β+ (99.7%) 161Lu 3/2-#
α (.3%) 157Yb
162Hf 72 90 161.94721(1) 39.4(9) sec β+ (99.99%) 162Lu 0+
α (.008%) 158Yb
163Hf 72 91 162.94709(3) 40.0(6) sec β+ 163Lu 3/2-#
α (10−4%) 159Yb
164Hf 72 92 163.944367(22) 111(8) sec β+ 164Lu 0+
165Hf 72 93 164.94457(3) 76(4) sec β+ 165Lu (5/2-)
166Hf 72 94 165.94218(3) 6.77(30) min β+ 166Lu 0+
167Hf 72 95 166.94260(3) 2.05(5) min β+ 167Lu (5/2)-
168Hf 72 96 167.94057(3) 25.95(20) min β+ 168Lu 0+
169Hf 72 97 168.94126(3) 3.24(4) min β+ 169Lu (5/2)-
170Hf 72 98 169.93961(3) 16.01(13) hr EC 170Lu 0+
171Hf 72 99 170.94049(3) 12.1(4) hr β+ 171Lu 7/2(+)
171mHf 21.93(9) keV 29.5(9) sec IT 171Hf 1/2(-)
172Hf 72 100 171.939448(26) 1.87(3) yr EC 172Lu 0+
172mHf 2005.58(11) keV 163(3) ns (8-)
173Hf 72 101 172.94051(3) 23.6(1) hr β+ 173Lu 1/2-
174Hf[n 4] 72 102 173.940046(3) 2.0(4)×1015 yr α 170Yb 0+ 0.0016(1) 0.001619-0.001621
174m1Hf 1549.3 keV 138(4) ns (6+)
174m2Hf 1797.5(20) keV 2.39(4) µs (8-)
174m3Hf 1797.5 keV 2.39(4) µs (8-)
174m4Hf 3311.7 keV 3.7(2) µs (14+)
175Hf 72 103 174.941509(3) 70(2) days β+ 175Lu 5/2-
176Hf[n 5] 72 104 175.9414086(24) Observationally Stable[n 6] 0+ 0.0526(7) 0.05206-0.05271
177Hf 72 105 176.9432207(23) Observationally Stable[n 7] 7/2- 0.1860(9) 0.18593-0.18606
177m1Hf 1315.4504(8) keV 1.09(5) sec 23/2+
177m2Hf 1342.38(20) keV 55.9(12) µs (19/2-)
177m3Hf 2740.02(15) keV 51.4(5) min 37/2-
178Hf 72 106 177.9436988(23) Observationally Stable[n 8][dubious ] 0+ 0.2728(7) 0.27278-0.27297
178m1Hf 1147.423(5) keV 4.0(2) sec 8-
178m2Hf 2445.69(11) keV 31(1) yr 16+
178m3Hf 2573.5(5) keV 68(2) µs (14-)
179Hf 72 107 178.9458161(23) Observationally Stable[n 9] 9/2+ 0.1362(2) 0.13619-0.1363
179m1Hf 375.0367(25) keV 18.67(4) sec 1/2-
179m2Hf 1105.84(19) keV 25.05(25) days 25/2-
180Hf 72 108 179.9465500(23) Observationally Stable[n 10] 0+ 0.3508(16) 0.35076-0.351
180m1Hf 1141.48(4) keV 5.47(4) hr 8-
180m2Hf 1374.15(4) keV 0.57(2) µs (4-)
180m3Hf 2425.8(10) keV 15(5) µs (10+)
180m4Hf 2486.3(9) keV 10(1) µs 12+
180m5Hf 2538.3(12) keV >10 µs (14+)
180m6Hf 3599.3(18) keV 90(10) µs (18-)
181Hf 72 109 180.9491012(23) 42.39(6) days β- 181Ta 1/2-
181m1Hf 595(3) keV 80(5) µs (9/2+)
181m2Hf 1040(10) keV ~100 µs (17/2+)
181m3Hf 1738(10) keV 1.5(5) ms (27/2-)
182Hf[n 11] 72 110 181.950554(7) 8.90(9)×106 yr β- 182W 0+
182mHf 1172.88(18) keV 61.5(15) min β- (58%) 182Ta 8-
IT (42%) 182Hf
183Hf 72 111 182.95353(3) 1.067(17) hr β- 183Ta (3/2-)
184Hf 72 112 183.95545(4) 4.12(5) hr β- 184Ta 0+
184mHf 1272.4(4) keV 48(10) sec β- 184Ta 8-
185Hf 72 113 184.95882(21)# 3.5(6) min β- 185Ta 3/2-#
186Hf 72 114 185.96089(32)# 2.6(12) min β- 186Ta 0+
187Hf 72 115 186.96459(43)# 30# s [>300 ns]
188Hf 72 116 187.96685(54)# 20# s [>300 ns] 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. ^ primordial radionuclide
  5. ^ Used in Lutetium-Hafnium dating
  6. ^ Believed to undergo α decay to 172Yb
  7. ^ Believed to undergo α decay to 173Yb
  8. ^ Believed to undergo α decay to 174Yb
  9. ^ Believed to undergo α decay to 175Yb
  10. ^ Believed to undergo α decay to 176Yb
  11. ^ Believed to occur naturally after the α decay of 186W (which is currently classified as stable)

Notes[edit]

  • Evaluated isotopic composition is for most but not all commercial samples.
  • 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. ^ http://www.nucleonica.net/unc.aspx


Isotopes of lutetium Isotopes of hafnium Isotopes of tantalum
Table of nuclides