Samarium-151m

Properties and data of the isotope ^151mSm.

Contents

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

General data

Name of the isotope:Samarium-151m; Sm-151mSymbol:^151mSm or 151m62SmMass number A:151 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:89Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4354838709677 (= neutron-proton ratio)Neutron excess (N-Z):27Excitation energy:261.13(4) keVIsotopic mass:150.9199391(14) u (atomic weight of Samarium-151m)Nuclide mass:150.8859298 u (calculated nuclear mass without electrons)Mass excess:-74.57625 MeVMass defect:1.336390408 u (per nucleus)Nuclear binding energy:1244.83964671 MeV (per nucleus)
8.24397117 MeV (average binding energy per nucleon)Half-life:1.4(1) μsDecay constant λ:495105.12897139 s^-1Specific activity α:1.987728551428 × 10⁺²⁷ Bq g^-1
5.372239328185 × 10⁺¹⁶ Ci g^-1Spin and parity:
(nuclear angular momentum)(11/2)-

Radioactive Decay

Half-life T_½ = 1.4(1) μs respectively 1.4 × 10^-6 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁵¹Sm	100 %

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
¹⁵¹Sm		90(8) a	5/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 89) and isobaric (same nucleon number A = 151) with Samarium-151m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 89	Isobar A = 151
50	¹³⁹Sn
51	¹⁴⁰Sb
52	¹⁴¹Te
53	¹⁴²I
54	¹⁴³Xe
55	¹⁴⁴Cs	¹⁵¹Cs
56	¹⁴⁵Ba	¹⁵¹Ba
57	¹⁴⁶La	¹⁵¹La
58	¹⁴⁷Ce	¹⁵¹Ce
59	¹⁴⁸Pr	¹⁵¹Pr
60	¹⁴⁹Nd	¹⁵¹Nd
61	¹⁵⁰Pm	¹⁵¹Pm
62	¹⁵¹Sm	¹⁵¹Sm
63	¹⁵²Eu	¹⁵¹Eu
64	¹⁵³Gd	¹⁵¹Gd
65	¹⁵⁴Tb	¹⁵¹Tb
66	¹⁵⁵Dy	¹⁵¹Dy
67	¹⁵⁶Ho	¹⁵¹Ho
68	¹⁵⁷Er	¹⁵¹Er
69	¹⁵⁸Tm	¹⁵¹Tm
70	¹⁵⁹Yb	¹⁵¹Yb
71	¹⁶⁰Lu	¹⁵¹Lu
72	¹⁶¹Hf
73	¹⁶²Ta
74	¹⁶³W
75	¹⁶⁴Re
76	¹⁶⁵Os
77	¹⁶⁶Ir
78	¹⁶⁷Pt