Lutetium-156

Properties and data of the isotope ¹⁵⁶Lu.

Contents

General data

Name of the isotope:Lutetium-156; Lu-156Symbol:¹⁵⁶Lu or 15671LuMass number A:156 (= number of nucleons)Atomic number Z:71 (= number of protons)Neutrons N:85Isotopic mass:155.95309(6) u (atomic weight of Lutetium-156)Nuclide mass:155.9141445 u (calculated nuclear mass without electrons)Mass excess:-43.69638 MeVMass defect:1.339005132 u (per nucleus)Nuclear binding energy:1247.27524643 MeV (per nucleus)
7.99535414 MeV (average binding energy per nucleon)Separation energy:S_N = 9.23(6) MeV (first neutron)
S_P = 0.49(6) MeV (first proton)Half-life:494(12) msDecay constant λ:1.4031319444533 s^-1Specific activity α:5.45152142875 × 10⁺²¹ Bq g^-1
147338416993.46 Ci g^-1Spin and parity:
(nuclear angular momentum)(2)-Year of discovery:1965

Radioactive Decay

Half-life T_½ = 494(12) ms respectively 4.94 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁵²Tm	ca. 95 %	5.596(3) MeV
EC/β⁺	¹⁵⁶Yb	ca. 5 %	9.57(5) MeV

Parent Nuclides

Direct parent isotope is: ¹⁶⁰Ta.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^156mLu	+x keV	198(2) ms	9+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 85) and isobaric (same nucleon number A = 156) with Lutetium-156. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 85	Isobar A = 156
47	¹³²Ag
48	¹³³Cd
49	¹³⁴In
50	¹³⁵Sn
51	¹³⁶Sb
52	¹³⁷Te
53	¹³⁸I
54	¹³⁹Xe
55	¹⁴⁰Cs
56	¹⁴¹Ba
57	¹⁴²La	¹⁵⁶La
58	¹⁴³Ce	¹⁵⁶Ce
59	¹⁴⁴Pr	¹⁵⁶Pr
60	¹⁴⁵Nd	¹⁵⁶Nd
61	¹⁴⁶Pm	¹⁵⁶Pm
62	¹⁴⁷Sm	¹⁵⁶Sm
63	¹⁴⁸Eu	¹⁵⁶Eu
64	¹⁴⁹Gd	¹⁵⁶Gd
65	¹⁵⁰Tb	¹⁵⁶Tb
66	¹⁵¹Dy	¹⁵⁶Dy
67	¹⁵²Ho	¹⁵⁶Ho
68	¹⁵³Er	¹⁵⁶Er
69	¹⁵⁴Tm	¹⁵⁶Tm
70	¹⁵⁵Yb	¹⁵⁶Yb
71	¹⁵⁶Lu	¹⁵⁶Lu
72	¹⁵⁷Hf	¹⁵⁶Hf
73	¹⁵⁸Ta	¹⁵⁶Ta
74	¹⁵⁹W	¹⁵⁶W
75	¹⁶⁰Re
76	¹⁶¹Os