Europium-140

Properties and data of the isotope ¹⁴⁰Eu.

Contents

General data

Name of the isotope:Europium-140; Eu-140Symbol:¹⁴⁰Eu or 14063EuMass number A:140 (= number of nucleons)Atomic number Z:63 (= number of protons)Neutrons N:77Isotopic mass:139.92809(6) u (atomic weight of Europium-140)Nuclide mass:139.8935322 u (calculated nuclear mass without electrons)Mass excess:-66.98373 MeVMass defect:1.232085548 u (per nucleus)Nuclear binding energy:1147.68029545 MeV (per nucleus)
8.1977164 MeV (average binding energy per nucleon)Separation energy:S_N = 9.66(5) MeV (first neutron)
S_P = 1.89(5) MeV (first proton)Half-life:1.51(2) sDecay constant λ:0.45903786792049 s^-1Specific activity α:1.988770288246 × 10⁺²¹ Bq g^-1
53750548330.978 Ci g^-1Spin and parity:
(nuclear angular momentum)1+Magnetic dipole moment:μ(μ_N) = + 1.365(13)Quadrupole moment Q:0.31(4) barn (100 fm²)Nuclear g-factor:g_l = 1.365Charge radius:4.9695(91) femtometer fmYear of discovery:1982

Radioactive Decay

Half-life T_½ = 1.51(2) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹⁴⁰Sm	100 %	8.47(5) MeV

Parent Nuclides

Direct parent isotope is: ¹⁴⁰Gd.

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
^140mEu	210(15) keV	125(2) ms	(5-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 77) and isobaric (same nucleon number A = 140) with Europium-140. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 77	Isobar A = 140
43	¹²⁰Tc
44	¹²¹Ru
45	¹²²Rh
46	¹²³Pd
47	¹²⁴Ag
48	¹²⁵Cd
49	¹²⁶In
50	¹²⁷Sn
51	¹²⁸Sb	¹⁴⁰Sb
52	¹²⁹Te	¹⁴⁰Te
53	¹³⁰I	¹⁴⁰I
54	¹³¹Xe	¹⁴⁰Xe
55	¹³²Cs	¹⁴⁰Cs
56	¹³³Ba	¹⁴⁰Ba
57	¹³⁴La	¹⁴⁰La
58	¹³⁵Ce	¹⁴⁰Ce
59	¹³⁶Pr	¹⁴⁰Pr
60	¹³⁷Nd	¹⁴⁰Nd
61	¹³⁸Pm	¹⁴⁰Pm
62	¹³⁹Sm	¹⁴⁰Sm
63	¹⁴⁰Eu	¹⁴⁰Eu
64	¹⁴¹Gd	¹⁴⁰Gd
65	¹⁴²Tb	¹⁴⁰Tb
66	¹⁴³Dy	¹⁴⁰Dy
67	¹⁴⁴Ho	¹⁴⁰Ho
68	¹⁴⁵Er
69	¹⁴⁶Tm