Lutetium-149

Properties and data of the isotope ¹⁴⁹Lu.

Content

Lutetium-149 is a radioisotope of the chemical element lutetium, which, in addition to the element-specific 71 protons, has 78 neutrons in the atomic nucleus, resulting in the mass number 149. The very short-lived, only artificially producible, unstable and therefore radioactive nuclide has no practical significance; dealing with ¹⁴⁹Lu is for academic purposes only.

The first report on the production and characterization of the nuclide ¹⁴⁹Lu dates from 2022; the synthesis succeeded through the reaction

⁹⁶Ru(⁵⁸Ni, p4n) ¹⁴⁹Lu.

The nucleus of the isotope is one of the less common proton emitters: With a half-life of just 450 nanoseconds, the atomic nucleus decays radioactively, emitting a proton, a positively charged nuclear building block.

The Finnish discoverers of the isotope list the flattened spherical shape of the Lu-149 atomic nucleus as a further special feature: the deviation from the expected perfect spherical shape of the atomic nucleus is the strongest ever measured for this nuclide; one could also describe this distortion as pumpkin-like [1].

General data

Name of the isotope:Lutetium-149; Lu-149Symbol:¹⁴⁹LuMass number A:149Atomic number Z:71 (= number of protons)Neutrons N:78Isotopic mass:149 u (atomic weight of Lutetium-149)Nuclide mass:148.9610545 u (calculated nuclear mass without electrons)Mass excess:0 MeVMass defect:1.23144072 u (per nucleus)Nuclear binding energy:1147.07964204 MeV (per nucleus)
7.69852109 MeV (average binding energy per nucleon)Half-life:450 nsSpin and parity:Year of discovery:2021

Radioactive Decay

Half-life T_½ = 450 ns.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
p	¹⁴⁸Yb

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 78) and isobaric (same nucleon number A = 149) with Lutetium-149. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 78	Isobar A = 149
43	¹²¹Tc
44	¹²²Ru
45	¹²³Rh
46	¹²⁴Pd
47	¹²⁵Ag
48	¹²⁶Cd
49	¹²⁷In
50	¹²⁸Sn
51	¹²⁹Sb
52	¹³⁰Te
53	¹³¹I
54	¹³²Xe
55	¹³³Cs	¹⁴⁹Cs
56	¹³⁴Ba	¹⁴⁹Ba
57	¹³⁵La	¹⁴⁹La
58	¹³⁶Ce	¹⁴⁹Ce
59	¹³⁷Pr	¹⁴⁹Pr
60	¹³⁸Nd	¹⁴⁹Nd
61	¹³⁹Pm	¹⁴⁹Pm
62	¹⁴⁰Sm	¹⁴⁹Sm
63	¹⁴¹Eu	¹⁴⁹Eu
64	¹⁴²Gd	¹⁴⁹Gd
65	¹⁴³Tb	¹⁴⁹Tb
66	¹⁴⁴Dy	¹⁴⁹Dy
67	¹⁴⁵Ho	¹⁴⁹Ho
68	¹⁴⁶Er	¹⁴⁹Er
69	¹⁴⁷Tm	¹⁴⁹Tm
70	¹⁴⁸Yb	¹⁴⁹Yb
71	¹⁴⁹Lu	¹⁴⁹Lu