Niobium-99

Properties and data of the isotope ⁹⁹Nb.

Contents

General data

Name of the isotope:Niobium-99; Nb-99Symbol:⁹⁹Nb or 9941NbMass number A:99 (= number of nucleons)Atomic number Z:41 (= number of protons)Neutrons N:58Isotopic mass:98.911609(13) u (atomic weight of Niobium-99)Nuclide mass:98.8891182 u (calculated nuclear mass without electrons)Mass excess:-82.33569 MeVMass defect:0.91178244000001 u (per nucleus)Nuclear binding energy:849.31987217 MeV (per nucleus)
8.57898861 MeV (average binding energy per nucleon)Separation energy:S_N = 6.882(13) MeV (first neutron)
S_P = 8.338(15) MeV (first proton)Half-life:15.0(2) sDecay constant λ:0.04620981203733 s^-1Specific activity α:2.839612216326 × 10⁺²⁰ Bq g^-1
7674627611.6932 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Magnetic dipole moment:μ(μ_N) = + 5.96(3)Quadrupole moment Q:0.42(14) barn (100 fm²)Nuclear g-factor:g_l = 1.3244444444444Charge radius:4.4062(125) femtometer fmYear of discovery:1950

Radioactive Decay

Half-life T_½ = 15.0(2) s respectively 1.50 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁹⁹Mo	100 %	3.635(12) MeV

Parent Nuclides

Direct parent isotope is: ⁹⁹Zr.

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
^99mNb	365.27(8) keV	2.5(2) min	1/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 58) and isobaric (same nucleon number A = 99) with Niobium-99. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 58	Isobar A = 99
32	⁹⁰Ge
33	⁹¹As
34	⁹²Se
35	⁹³Br
36	⁹⁴Kr	⁹⁹Kr
37	⁹⁵Rb	⁹⁹Rb
38	⁹⁶Sr	⁹⁹Sr
39	⁹⁷Y	⁹⁹Y
40	⁹⁸Zr	⁹⁹Zr
41	⁹⁹Nb	⁹⁹Nb
42	¹⁰⁰Mo	⁹⁹Mo
43	¹⁰¹Tc	⁹⁹Tc
44	¹⁰²Ru	⁹⁹Ru
45	¹⁰³Rh	⁹⁹Rh
46	¹⁰⁴Pd	⁹⁹Pd
47	¹⁰⁵Ag	⁹⁹Ag
48	¹⁰⁶Cd	⁹⁹Cd
49	¹⁰⁷In	⁹⁹In
50	¹⁰⁸Sn	⁹⁹Sn
51	¹⁰⁹Sb
52	¹¹⁰Te
53	¹¹¹I
54	¹¹²Xe
55	¹¹³Cs
56	¹¹⁴Ba