Strontium-84

Properties and data of the isotope ⁸⁴Sr.

Contents

Strontium-84 is a naturally occurring, stable and therefore non-radioactive isotope of the chemical element strontium with atomic number 38 and mass number 84. It consists of a nucleus of 38 protons and 46 neutrons.

⁸⁴Sr is one of the most common Sr isotopes and is found in small amounts in minerals and soil. It is used in industry to produce strontium salts used in pyrotechnics, glass making and chemical analysis. Strontium-84 can also be used as a standard in mass spectrometry and serves as a reference for the determination of other isotopes.

Sr-84 is used in medical diagnostics as a marker for bone and tooth mineralization.

General data

Name of the isotope:Strontium-84; Sr-84Symbol:⁸⁴Sr or 8438SrMass number A:84 (= number of nucleons)Atomic number Z:38 (= number of protons)Neutrons N:46Isotopic mass:83.913419(8) u (atomic weight of Strontium-84)Nuclide mass:83.8925738 u (calculated nuclear mass without electrons)Mass excess:-80.64968 MeVMass defect:0.782518352 u (per nucleus)Nuclear binding energy:728.91114978 MeV (per nucleus)
8.67751369 MeV (average binding energy per nucleon)Separation energy:S_N = 11.923(7) MeV (first neutron)
S_P = 8.8679(26) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:4.2394(23) femtometer fmYear of discovery:1936

Parent Nuclides

Direct parent isotopes are: ⁸⁴Y, ⁸⁴Rb.

Occurrence

Comparison of the natural Strontium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Strontium Isotopic mixture	87.62 u	100 %
Isotope ⁸⁴Sr	83.913419(8) u	0.57 % [0.55 - 0.58 %]	stable	0+
Isotope ⁸⁶Sr	85.909261(8) u	9.87 % [9.75 - 9.99 %]	stable	0+
Isotope ⁸⁸Sr	87.905613(8) u	82.52 % [82.29 - 82.75 %]	stable	0+
Isotope ⁸⁷Sr	86.908878(8) u	7.00(20) % [6.94 - 7.14 %]	stable	9/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 46) and isobaric (same nucleon number A = 84) with Strontium-84. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 46	Isobar A = 84
25	⁷¹Mn
26	⁷²Fe
27	⁷³Co
28	⁷⁴Ni
29	⁷⁵Cu
30	⁷⁶Zn	⁸⁴Zn
31	⁷⁷Ga	⁸⁴Ga
32	⁷⁸Ge	⁸⁴Ge
33	⁷⁹As	⁸⁴As
34	⁸⁰Se	⁸⁴Se
35	⁸¹Br	⁸⁴Br
36	⁸²Kr	⁸⁴Kr
37	⁸³Rb	⁸⁴Rb
38	⁸⁴Sr	⁸⁴Sr
39	⁸⁵Y	⁸⁴Y
40	⁸⁶Zr	⁸⁴Zr
41	⁸⁷Nb	⁸⁴Nb
42	⁸⁸Mo	⁸⁴Mo
43	⁸⁹Tc
44	⁹⁰Ru
45	⁹¹Rh
46	⁹²Pd
47	⁹³Ag
48	⁹⁴Cd