Lanthanum-117m

Properties and data of the isotope ¹¹⁷La.

Content

General data

Name of the isotope:Lanthanum-117m; La-117mSymbol:¹¹⁷La or 11757LaMass number A:117 (= number of nucleons)Atomic number Z:57 (= number of protons)Neutrons N:60Isotopic mass:116.95011(21) u (atomic weight of Lanthanum-117m)
Excitation energy: 151(12) keVNuclide mass:116.9188431 u (calculated nuclear mass without electrons)Mass excess:-46.47224 MeVMass defect:1.015811784 u (per nucleus)Nuclear binding energy:946.22258193 MeV (per nucleus)
8.0873725 MeV (average binding energy per nucleon)Half-life:10(5) msDecay constant λ:69.314718055995 s^-1Specific activity α:3.598474101724 × 10⁺²³ Bq g^-1
9725605680335.4 Ci g^-1Spin and parity:
(nuclear angular momentum)(9/2+)

Radioactive Decay

Half-life T_½ = 10(5) ms respectively 1.0 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
p	¹¹⁶Ba	97.4(13) %
β⁺	¹¹⁷Ba	2.6(13) %

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
¹¹⁷La		23.5(25) ms	(3/2)+-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 60) and isobaric (same nucleon number A = 117) with Lanthanum-117m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 60	Isobar A = 117
34	⁹⁴Se
35	⁹⁵Br
36	⁹⁶Kr
37	⁹⁷Rb
38	⁹⁸Sr
39	⁹⁹Y
40	¹⁰⁰Zr
41	¹⁰¹Nb
42	¹⁰²Mo	¹¹⁷Mo
43	¹⁰³Tc	¹¹⁷Tc
44	¹⁰⁴Ru	¹¹⁷Ru
45	¹⁰⁵Rh	¹¹⁷Rh
46	¹⁰⁶Pd	¹¹⁷Pd
47	¹⁰⁷Ag	¹¹⁷Ag
48	¹⁰⁸Cd	¹¹⁷Cd
49	¹⁰⁹In	¹¹⁷In
50	¹¹⁰Sn	¹¹⁷Sn
51	¹¹¹Sb	¹¹⁷Sb
52	¹¹²Te	¹¹⁷Te
53	¹¹³I	¹¹⁷I
54	¹¹⁴Xe	¹¹⁷Xe
55	¹¹⁵Cs	¹¹⁷Cs
56	¹¹⁶Ba	¹¹⁷Ba
57	¹¹⁷La	¹¹⁷La