Rhodium-99

Properties and data of the isotope ⁹⁹Rh.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Rhodium-99; Rh-99Symbol:⁹⁹Rh or 9945RhMass number A:99 (= number of nucleons)Atomic number Z:45 (= number of protons)Neutrons N:54Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2 (= neutron-proton ratio)Neutron excess (N-Z):9Isotopic mass:98.908125(7) u (atomic weight of Rhodium-99)Nuclide mass:98.8834402 u (calculated nuclear mass without electrons)Mass excess:-85.58101 MeVMass defect:0.91190690400001 u (per nucleus)Nuclear binding energy:849.43580963 MeV (per nucleus)
8.58015969 MeV (average binding energy per nucleon)Separation energy:S_N = 10.477(14) MeV (first neutron)
S_P = 4.645(9) MeV (first proton)Half-life:16.1(2) dDecay constant λ:4.982942119277 × 10^-7 s^-1Specific activity α:3.062038708081 × 10⁺¹⁵ Bq g^-1
82757.802921124 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2-Year of discovery:1952

Radioactive Decay

Half-life T_½ = 16.1(2) d respectively 1.391040 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	⁹⁹Ru	100 %	2.044(7) MeV

Parent Nuclides

Direct parent isotope is: ⁹⁹Pd.

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
^99mRh	64.4(5) keV	4.7(1) h	9/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 54) and isobaric (same nucleon number A = 99) with Rhodium-99. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 54	Isobar A = 99
30	⁸⁴Zn
31	⁸⁵Ga
32	⁸⁶Ge
33	⁸⁷As
34	⁸⁸Se
35	⁸⁹Br
36	⁹⁰Kr	⁹⁹Kr
37	⁹¹Rb	⁹⁹Rb
38	⁹²Sr	⁹⁹Sr
39	⁹³Y	⁹⁹Y
40	⁹⁴Zr	⁹⁹Zr
41	⁹⁵Nb	⁹⁹Nb
42	⁹⁶Mo	⁹⁹Mo
43	⁹⁷Tc	⁹⁹Tc
44	⁹⁸Ru	⁹⁹Ru
45	⁹⁹Rh	⁹⁹Rh
46	¹⁰⁰Pd	⁹⁹Pd
47	¹⁰¹Ag	⁹⁹Ag
48	¹⁰²Cd	⁹⁹Cd
49	¹⁰³In	⁹⁹In
50	¹⁰⁴Sn	⁹⁹Sn
51	¹⁰⁵Sb
52	¹⁰⁶Te