Lanthanum-117

Properties and data of the isotope ¹¹⁷La.

Contents

General data

Name of the isotope:Lanthanum-117; La-117Symbol: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-117)Nuclide 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)Separation energy:S_N = 13.90(337) MeV (first neutron)Half-life:23.5(25) msDecay constant λ:29.495624704679 s^-1Specific activity α:1.531265575201 × 10⁺²³ Bq g^-1
4138555608653.5 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2)+-Year of discovery:2001

Radioactive Decay

Half-life T_½ = 23.5(25) ms respectively 2.35 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
p	¹¹⁶Ba	93.9(7) %
β⁺	¹¹⁷Ba	6.1(7) %	10.99(32) MeV

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
^117mLa	151(12) keV	10(5) ms	(9/2+)

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-117. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	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