Europium-135

Properties and data of the isotope ¹³⁵Eu.

Contents

See also: List of individual Europium isotopes (and general data sources).

General data

Name of the isotope:Europium-135; Eu-135Symbol:¹³⁵Eu or 13563EuMass number A:135 (= number of nucleons)Atomic number Z:63 (= number of protons)Neutrons N:72Isotopic mass:134.94187(21) u (atomic weight of Europium-135)Nuclide mass:134.9073122 u (calculated nuclear mass without electrons)Mass excess:-54.14775 MeVMass defect:1.174980968 u (per nucleus)Nuclear binding energy:1094.48772181 MeV (per nucleus)
8.10731646 MeV (average binding energy per nucleon)Separation energy:S_N = 12.29(36) MeV (first neutron)
S_P = 0.06 MeV (first proton)Half-life:1.5(2) sDecay constant λ:0.4620981203733 s^-1Specific activity α:2.076731322388 × 10⁺²¹ Bq g^-1
56127873578.057 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-Year of discovery:1989

Radioactive Decay

Half-life T_½ = 1.5(2) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹³⁵Sm	100 %	8.71(25) MeV
EC, p	¹³⁴Pm	?

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 72) and isobaric (same nucleon number A = 135) with Europium-135. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 72	Isobar A = 135
40	¹¹²Zr
41	¹¹³Nb
42	¹¹⁴Mo
43	¹¹⁵Tc
44	¹¹⁶Ru
45	¹¹⁷Rh
46	¹¹⁸Pd
47	¹¹⁹Ag
48	¹²⁰Cd
49	¹²¹In	¹³⁵In
50	¹²²Sn	¹³⁵Sn
51	¹²³Sb	¹³⁵Sb
52	¹²⁴Te	¹³⁵Te
53	¹²⁵I	¹³⁵I
54	¹²⁶Xe	¹³⁵Xe
55	¹²⁷Cs	¹³⁵Cs
56	¹²⁸Ba	¹³⁵Ba
57	¹²⁹La	¹³⁵La
58	¹³⁰Ce	¹³⁵Ce
59	¹³¹Pr	¹³⁵Pr
60	¹³²Nd	¹³⁵Nd
61	¹³³Pm	¹³⁵Pm
62	¹³⁴Sm	¹³⁵Sm
63	¹³⁵Eu	¹³⁵Eu
64	¹³⁶Gd	¹³⁵Gd
65	¹³⁷Tb	¹³⁵Tb
66	¹³⁸Dy