Isotopes of Strontium

List, data and properties of all known isotopes of Strontium.

Content

Atomic properties

Decay properties

NMR active nuclides

Radiation protection

References

All atomic nuclei of the chemical element strontium are summarized under strontium isotopes; these all consist of an atomic nucleus with 38 protons and, in the uncharged state, 38 electrons. The difference between each strontium isotope is based on the number of neutrons in the nucleus.

Naturally Occurring Strontium Isotopes

Of the four stable strontium isotopes found in nature, the isotope ⁸⁸Sr is the most common nuclide with a proportion of over 82%. Sr-87 enters nature as a stable decay product of the radioactive rubidium isotope Rb-87.

	Atomic Mass m_a	Quantity	Half-life	Spin
Strontium Isotopic mixture	87,62 u	100 %
Isotope ⁸⁴Sr	83,913419(8) u	0,57 %	stable	0+
Isotope ⁸⁶Sr	85,909261(8) u	9,87 %	stable	0+
Isotope ⁸⁸Sr	87,905613(8) u	82,52 %	stable	0+
Isotope ⁸⁷Sr	86,908878(8) u	7,00(20) %	stable	9/2+

The other known isotopes and nuclear isomers are unstable radioisotopes, of which in particular the anthropogenically produced Sr-90 occasionally escapes into the environment and causes radiation damage.

Isotope Table: Strontium

The two following tables list the most important data and properties of the Strontium isotopes. Further information on the individual Strontium isotopes is listed on separate pages and can be accessed via the link in column 1.

Atomic Properties

Isotope Nuclide	E	N	Atomic Mass [Nuclear Mass] {Mass Excess}	Spin I (h/2π)	Parent
1	2	3	4	5	6
Strontium-73	7338Sr	35	72.96570(43) u [72.9448548 u] {-31.95024 MeV}	5/2-
Strontium-74	7438Sr	36	73.95617(11) u [73.9353248 u] {-40.82738 MeV}	0+
Strontium-75	7538Sr	37	74.94995(24) u [74.9291048 u] {-46.62127 MeV}	(3/2-)	⁷⁶Y
Strontium-76	7638Sr	38	75.94176(4) u [75.9209148 u] {-54.25021 MeV}	0+
Strontium-77	7738Sr	39	76.937945(8) u [76.9170998 u] {-57.80386 MeV}	5/2(+)	⁷⁷Y
Strontium-78	7838Sr	40	77.932180(8) u [77.9113348 u] {-63.17392 MeV}	0+	⁷⁸Y
Strontium-79	7938Sr	41	78.929708(9) u [78.9088628 u] {-65.47658 MeV}	3/2(-)	⁷⁹Y
Strontium-80	8038Sr	42	79.924518(4) u [79.9036728 u] {-70.31103 MeV}	0+	⁸⁰Y
Strontium-81	8138Sr	43	80.923211(3) u [80.9023658 u] {-71.52849 MeV}	1/2-	⁸¹Y
Strontium-82	8238Sr	44	81.918400(6) u [81.8975548 u] {-76.00991 MeV}	0+	⁸²Y
Strontium-83	8338Sr	45	82.917554(7) u [82.8967088 u] {-76.79795 MeV}	7/2+	⁸³Y
Strontium-83m	83m38Sr	45	82.917554(7) u [82.8967088 u] {-76.79795 MeV}	1/2-
Strontium-84	8438Sr	46	83.913419(8) u [83.8925738 u] {-80.64968 MeV}	0+	⁸⁴Y ⁸⁴Rb
Strontium-85	8538Sr	47	84.912932(3) u [84.8920868 u] {-81.10332 MeV}	9/2+	⁸⁵Y
Strontium-85m	85m38Sr	47	84.912932(3) u [84.8920868 u] {-81.10332 MeV}	1/2-
Strontium-86	8638Sr	48	85.909261(8) u [85.8884158 u] {-84.52283 MeV}	0+	⁸⁶Y ⁸⁶Rb
Strontium-86m	86m38Sr	48	85.909261(8) u [85.8884158 u] {-84.52283 MeV}	8+
Strontium-87	8738Sr	49	86.908878(8) u [86.8880328 u] {-84.8796 MeV}	9/2+	⁸⁷Y ⁸⁷Rb
Strontium-87m	87m38Sr	49	86.908878(8) u [86.8880328 u] {-84.8796 MeV}	1/2-
Strontium-88	8838Sr	50	87.905613(8) u [87.8847678 u] {-87.92092 MeV}	0+	⁸⁸Y ⁸⁸Rb
Strontium-89	8938Sr	51	88.90745081(10) u [88.8866056 u] {-86.20902 MeV}	5/2+	⁸⁹Rb
Strontium-90	9038Sr	52	89.9077279(16) u [89.8868827 u] {-85.95091 MeV}	0+	⁹⁰Rb
Strontium-91	9138Sr	53	90.910196(6) u [90.8893508 u] {-83.65189 MeV}	5/2+	⁹¹Rb
Strontium-92	9238Sr	54	91.911038(4) u [91.8901928 u] {-82.86757 MeV}	0+	⁹²Rb
Strontium-93	9338Sr	55	92.914024(8) u [92.8931788 u] {-80.08613 MeV}	5/2+	⁹³Rb
Strontium-94	9438Sr	56	93.9153556(18) u [93.8945104 u] {-78.84575 MeV}	0+	⁹⁴Rb
Strontium-95	9538Sr	57	94.919356(6) u [94.8985108 u] {-75.1194 MeV}	1/2+	⁹⁵Rb
Strontium-96	9638Sr	58	95.921713(9) u [95.9008678 u] {-72.92387 MeV}	0+	⁹⁶Rb
Strontium-97	9738Sr	59	96.926375(4) u [96.9055298 u] {-68.58125 MeV}	1/2+	⁹⁷Rb
Strontium-97m1	97m138Sr	59	96.926375(4) u [96.9055298 u] {-68.58125 MeV}	7/2+
Strontium-97m2	97m238Sr	59	96.926375(4) u [96.9055298 u] {-68.58125 MeV}	(9/2+)
Strontium-98	9838Sr	60	97.928692(3) u [97.9078468 u] {-66.42297 MeV}	0+	⁹⁸Rb
Strontium-99	9938Sr	61	98.932881(5) u [98.9120358 u] {-62.52095 MeV}	3/2+	⁹⁹Rb
Strontium-100	10038Sr	62	99.935780(8) u [99.9149348 u] {-59.82054 MeV}	0+	¹⁰⁰Rb
Strontium-101	10138Sr	63	100.940606(9) u [100.9197608 u] {-55.32515 MeV}	(5/2-)	¹⁰¹Rb
Strontium-102	10238Sr	64	101.94400(7) u [101.9231548 u] {-52.16366 MeV}	0+	¹⁰²Rb
Strontium-103	10338Sr	65	102.94909(21) u [102.9282448 u] {-47.42236 MeV}
Strontium-104	10438Sr	66	103.95265(32) u [103.9318048 u] {-44.10624 MeV}	0+
Strontium-105	10538Sr	67	104.95855(54) u [104.9377048 u] {-38.61043 MeV}
Strontium-106	10638Sr	68	105.96265(64) u [105.9418048 u] {-34.7913 MeV}	0+
Strontium-107	10738Sr	69	106.96897(75) u [106.9481248 u] {-28.90426 MeV}

Radioactive Decay Properties

Isotope	Radioactive Decay				Extern
	Half-life	Decay Mode	Probability	Energy
7	8	9	10	11	12
Sr-73	28 ms	β⁺ → ⁷³Rb EC, p → ⁷²Kr	< 100 % ?	14.062(403) MeV	AL
Sr-74	27(8) ms	EC/β⁺ → ⁷⁴Rb EC, p → ⁷³Kr	?	11.09(10) MeV	AL
Sr-75	88(3) ms	EC/β⁺ → ⁷⁵Rb EC, p → ⁷⁴Kr	94.8 % 5.2(9) %	10.60(22) MeV	AL
Sr-76	7.89(7) s	EC/β⁺ → ⁷⁶Rb EC, p → ⁷⁵Kr	< 100 % > 0 %	6.23(30) MeV	AL
Sr-77	9.0(2) s	EC/β⁺ → ⁷⁷Rb EC, p → ⁷⁶Kr	99.92 % 0.08(3) %	7.027(8)	AL
Sr-78	160(8) s	EC/β⁺ → ⁷⁸Rb	100 %	3.761(8) MeV	AL
Sr-79	2.25(10) min	EC/β⁺ → ⁷⁹Rb	100 %	5.326(9) MeV	AL
Sr-80	106.3(15) min	EC/β⁺ → ⁸⁰Rb	100 %	1.864(4) MeV	AL
Sr-81	22.3(4) min	EC/β⁺ → ⁸¹Rb	100 %	3.929(6) MeV	AL
Sr-82	25.35(3) d	EC → ⁸²Rb		0.178(7) MeV	AL
Sr-83	32.41(3) h	EC/β⁺ → ⁸³Rb	100 %	2.273(7) MeV	AL
Sr-83m	4.95(12) s	Iso → ⁸³Sr	100%		AL
Sr-84	stable				AL
Sr-85	64.849(7) d	EC → ⁸⁵Rb	100%	1.0640(28) MeV	AL
Sr-85m	67.63(4) min	Iso → ⁸⁵Sr EC → ⁸⁵Rb	86.6(4) % 13.4(4) %		AL
Sr-86	stable				AL
Sr-86m	455(7) ns	Iso → ⁸⁶Sr	100 %		AL
Sr-87	stable				AL
Sr-87m	2.815(12) h	Iso → ⁸⁷Sr EC → ⁸⁷Rb	99.70(8) % 0.30(8) %		AL
Sr-88	stable				AL
Sr-89	50.563(25) d	β^- → ⁸⁹Y	100%	1.5022(4) MeV	AL
Sr-90	28.91(3) a	β^- → ⁹⁰Y	100%	0.5460(14) MeV	AL
Sr-91	9.65(6) h	β^- → ⁹¹Y	100%	2.699(5) MeV	AL
Sr-92	2.611(17) h	β^- → ⁹²Y	100%	1.949(9) MeV	AL
Sr-93	7.43(3) min	β^- → ⁹³Y	100%	4.141(12) MeV	AL
Sr-94	75.3(2) s	β^- → ⁹⁴Y	100%	3.506(6) MeV	AL
Sr-95	23.90(14) s	β^- → ⁹⁵Y	100%	6.089(7) MeV	AL
Sr-96	1.07(1) s	β^- → ⁹⁶Y	100%	5.412(10) MeV	AL
Sr-97	429(5) ms	β^- → ⁹⁷Y β^-, n → ⁹⁶Y	99.95 % 0.05 %	7.540(8) MeV 1.683(7)	AL
Sr-97m1	169(9) ns				AL
Sr-97m2	395 ns				AL
Sr-98	653(2) ms	β^- → ⁹⁸Y β^-, n → ⁹⁷Y	99.75 % 0.25(5) %	5.872(9) MeV 1.627(7) MeV	AL
Sr-99	269(1) ms	β^- → ⁹⁹Y β^-, n → ⁹⁸Y	99.9 % 0.1 %	8.128(8) MeV 1.702(9) MeV	AL
Sr-100	202(3) ms	β^- → ¹⁰⁰Y β^-, n → ⁹⁹Y	99.22 % 0.78(13) %	7.506(13) MeV 2.758(10) MeV	AL
Sr-101	118(3) ms	β^- → ¹⁰¹Y β^-, n → ¹⁰⁰Y	97.63 % 2.37(14) %	9.736(11) MeV 3.931(14) MeV	AL
Sr-102	69(6) ms	β^- → ¹⁰²Y β^-, n → ¹⁰¹Y	94.5 % 5.5(15) %	9.01(7) MeV 4.83(7) MeV	AL
Sr-103	53(10) ms	β^- → ¹⁰³Y β^-, n → ¹⁰²Y β^-, 2n → ¹⁰¹Y	? ?	11.03(20) MeV 5.68(20) MeV	AL
Sr-104	53(5) ms	β^- → ¹⁰⁴Y β^-, n → ¹⁰³Y β^-, 2n → ¹⁰²Y		9.96(50) MeV 6.28(30) MeV	AL
Sr-105	39(5) ms	β^- → ¹⁰⁵Y β^-, n → ¹⁰⁴Y β^-, 2n → ¹⁰³Y	? ?	12.66 MeV 7.38(64) MeV	AL
Sr-106	20 ms	β^- → ¹⁰⁶Y β^-, n → ¹⁰⁵Y β^-, 2n → ¹⁰⁴Y		11.26(78) MeV 8.41(146) MeV	AL
Sr-107	395 ns	β^- → ¹⁰⁷Y β^-, n → ¹⁰⁶Y β^-, 2n → ¹⁰⁵Y	? ? ?	13.46(86) MeV 9.08(86) MeV	AL

Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Strontium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to ¹²C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.
8 - decay: half-live of the Strontium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β^- = beta minus decay with electron emission; EC = electron capture; β⁺ = positron emission; ε = β⁺ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
- unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

NMR active Strontium nuclides

Nuclide quantity ¹) spin	Nuclear magnetic moment μ/μ_N	Gyromagnetic ratio {Quadrupole moment}	Resonant frequency v₀ bei 1 T	Relative sensitivity H₀ = const. v₀ = const. ³)
⁸⁷Sr 7,00(20) % 9/2+	-1,09316(11)	- 1,1639376 {+ 0,305(2)}	1,8525	0,00272 1,4358

¹) Quantity Percentage of natural occurrence.

²) Gyromagnetic ratio: 10⁷ rad T^-1 s^-1
Quadrupole moment: Q [barn] = [100 fm²]

³) Related to ¹H = 1,000.

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Strontium radionuclides:

Nuclide	Limit Value		HASS limit	SC	Daughter Nuclides	Half-life
Sr-80+	10⁷ Bq	1000 Bq/g				1.8 h
Sr-81	10⁵ Bq	10 Bq/g				22.3 min
Sr-82+	10⁵ Bq	1 Bq/g	0,06 TBq		Rb-82	25.4 d
Sr-83	10⁶ Bq	10 Bq/g				32.4 h
Sr-85	10⁶ Bq	1 Bq/g	0,1 TBq	1 Bq cm^-2		64.8 d
Sr-85m	10⁷ Bq	100 Bq/g	0,1 T Bq	10 Bq cm^-2		67.6 min
Sr-87m	10⁶ Bq	100 Bq/g	0,2 TBq	10 Bq cm^-2		2.8 h
Sr-89+	10⁶ Bq	1000 Bq/g	20 TBq	100 Bq cm^-2		50.6 d
Sr-90+	10⁴ Bq	1 Bq/g	1 TBq	1 Bq cm^-2	Y-90	28.8 a
Sr-91+	10⁵ Bq	10 Bq/g	0,06 TBq	1 Bq cm^-2		9.6 h
Sr-92	10⁶ Bq	10 Bq/g	0,04 TBq	1 Bq cm^-2		2.7 h

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

Literature Sources and References

Properties of the Strontium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Strontium: NMR properties - ⁸⁷Sr-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - NN:
Bestimmung von radioaktivem Strontium in der Umwelt.
In: Internetchemie News, (2008).

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