Yttrium-90

Properties and data of the isotope ⁹⁰Y.

Contents

Yttrium-90 is a radioisotope of the chemical element yttrium, which, in addition to the element-specific 39 protons, has 51 neutrons in the atomic nucleus, resulting in the mass number 90.

The radioactive ⁹⁰Y nuclide is used in medicine in the radiation therapy of certain types of cancer (see below).

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

General data

Name of the isotope:Yttrium-90; Y-90Symbol:⁹⁰Y or 9039YMass number A:90 (= number of nucleons)Atomic number Z:39 (= number of protons)Neutrons N:51Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.3076923076923 (= neutron-proton ratio)Neutron excess (N-Z):12Isotopic mass:89.9071417(4) u (atomic weight of Yttrium-90)Nuclide mass:89.885748 u (calculated nuclear mass without electrons)Mass excess:-86.49695 MeVMass defect:0.83994526400001 u (per nucleus)Nuclear binding energy:782.40397374 MeV (per nucleus)
8.69337749 MeV (average binding energy per nucleon)Separation energy:S_N = 6.85703(10) MeV (first neutron)
S_P = 7.5769(4) MeV (first proton)Half-life:64.05(5) hDecay constant λ:3.006102786711 × 10^-6 s^-1Specific activity α:2.034064541688 × 10⁺¹⁶ Bq g^-1
549747.17342924 Ci g^-1Spin and parity:
(nuclear angular momentum)2-Magnetic dipole moment:μ(μ_N) = -1.630(8)Quadrupole moment Q:-0.125(11) barn (100 fm²)Nuclear g-factor:g_l = -0.815Charge radius:4.2573(26) femtometer fmYear of discovery:1937

Radioactive Decay

Half-life T_½ = 64.05(5) h (hours) respectively 2.30580 × 10⁵ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁹⁰Zr	100 %	2.2756(4) MeV

Parent Nuclides

Direct parent isotope is: ⁹⁰Sr.

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
^90mY	681.67(10) keV	3.19(6) h	7+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 51) and isobaric (same nucleon number A = 90) with Yttrium-90. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 51	Isobar A = 90
28	⁷⁹Ni
29	⁸⁰Cu
30	⁸¹Zn
31	⁸²Ga
32	⁸³Ge	⁹⁰Ge
33	⁸⁴As	⁹⁰As
34	⁸⁵Se	⁹⁰Se
35	⁸⁶Br	⁹⁰Br
36	⁸⁷Kr	⁹⁰Kr
37	⁸⁸Rb	⁹⁰Rb
38	⁸⁹Sr	⁹⁰Sr
39	⁹⁰Y	⁹⁰Y
40	⁹¹Zr	⁹⁰Zr
41	⁹²Nb	⁹⁰Nb
42	⁹³Mo	⁹⁰Mo
43	⁹⁴Tc	⁹⁰Tc
44	⁹⁵Ru	⁹⁰Ru
45	⁹⁶Rh	⁹⁰Rh
46	⁹⁷Pd	⁹⁰Pd
47	⁹⁸Ag
48	⁹⁹Cd
49	¹⁰⁰In
50	¹⁰¹Sn