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Krypton-81m

Другие языки:

Krypton-81m

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Main isotopes			Decay
	abundance	half-life (t_1/2)	mode	product
⁷⁸Kr	0.360%	9.2×10²¹ y	εε	⁷⁸Se
⁷⁹Kr	synth	35 h	ε	⁷⁹Br
			β⁺	⁷⁹Br
			γ	–
⁸⁰Kr	2.29%	stable
⁸¹Kr	trace	2.3×10⁵ y	ε	⁸¹Br
^81mKr		13.10 s	IT	⁸¹Kr
^81mKr		13.10 s	ε	⁸¹Br
⁸²Kr	11.6%	stable
⁸³Kr	11.5%	stable
⁸⁴Kr	57.0%	stable
⁸⁵Kr	synth	11 y	β⁻	⁸⁵Rb
⁸⁶Kr	17.3%	stable

Standard atomic weight A_r°(Kr)

83.798±0.002
83.798±0.002 (abridged)

There are 34 known isotopes of krypton (₃₆Kr) with atomic mass numbers from 69 through 102. Naturally occurring krypton is made of five stable isotopes and one (⁷⁸
Kr
) which is slightly radioactive with an extremely long half-life, plus traces of radioisotopes that are produced by cosmic rays in the atmosphere.

List of isotopes

Nuclide	Z	N	Isotopic mass (Da)	Half-life	Decay mode	Daughter isotope	Spin and parity	Natural abundance (mole fraction)
Nuclide	Excitation energy			Half-life	Decay mode	Daughter isotope	Spin and parity	Normal proportion	Range of variation
⁶⁹Kr	36	33	68.96518(43)#	32(10) ms	β⁺	⁶⁹Br	5/2−#
⁷⁰Kr	36	34	69.95526(41)#	52(17) ms	β⁺	⁷⁰Br	0+
⁷¹Kr	36	35	70.94963(70)	100(3) ms	β⁺ (94.8%)	⁷¹Br	(5/2)−
⁷¹Kr	36	35	70.94963(70)	100(3) ms	β⁺, p (5.2%)	⁷⁰Se	(5/2)−
⁷²Kr	36	36	71.942092(9)	17.16(18) s	β⁺	⁷²Br	0+
⁷³Kr	36	37	72.939289(7)	28.6(6) s	β⁺ (99.32%)	⁷³Br	3/2−
⁷³Kr	36	37	72.939289(7)	28.6(6) s	β⁺, p (.68%)	⁷²Se	3/2−
^73mKr	433.66(12) keV			107(10) ns			(9/2+)
⁷⁴Kr	36	38	73.9330844(22)	11.50(11) min	β⁺	⁷⁴Br	0+
⁷⁵Kr	36	39	74.930946(9)	4.29(17) min	β⁺	⁷⁵Br	5/2+
⁷⁶Kr	36	40	75.925910(4)	14.8(1) h	β⁺	⁷⁶Br	0+
⁷⁷Kr	36	41	76.9246700(21)	74.4(6) min	β⁺	⁷⁷Br	5/2+
⁷⁸Kr	36	42	77.9203648(12)	9.2 ^+5.5 _−2.6 ±1.3×10²¹ y	Double EC	⁷⁸Se	0+	0.00355(3)
⁷⁹Kr	36	43	78.920082(4)	35.04(10) h	β⁺	⁷⁹Br	1/2−
^79mKr	129.77(5) keV			50(3) s			7/2+
⁸⁰Kr	36	44	79.9163790(16)	Stable			0+	0.02286(10)
⁸¹Kr	36	45	80.9165920(21)	2.29(11)×10⁵ y	EC	⁸¹Br	7/2+	trace
^81mKr	190.62(4) keV			13.10(3) s	IT (99.975%)	⁸¹Kr	1/2−
^81mKr	190.62(4) keV			13.10(3) s	EC (.025%)	⁸¹Br	1/2−
⁸²Kr	36	46	81.9134836(19)	Stable			0+	0.11593(31)
⁸³Kr	36	47	82.914136(3)	Stable			9/2+	0.11500(19)
^83m1Kr	9.4053(8) keV			154.4(11) ns			7/2+
^83m2Kr	41.5569(10) keV			1.83(2) h	IT	⁸³Kr	1/2−
⁸⁴Kr	36	48	83.911507(3)	Stable			0+	0.56987(15)
^84mKr	3236.02(18) keV			1.89(4) µs			8+
⁸⁵Kr	36	49	84.9125273(21)	10.776(3) y	β⁻	⁸⁵Rb	9/2+	trace
^85m1Kr	304.871(20) keV			4.480(8) h	β⁻ (78.6%)	⁸⁵Rb	1/2−
^85m1Kr	304.871(20) keV			4.480(8) h	IT (21.4%)	⁸⁵Kr	1/2−
^85m2Kr	1991.8(13) keV			1.6(7) µs [1.2(+10-4) µs]			(17/2+)
⁸⁶Kr	36	50	85.91061073(11)	Observationally Stable			0+	0.17279(41)
⁸⁷Kr	36	51	86.91335486(29)	76.3(5) min	β⁻	⁸⁷Rb	5/2+
⁸⁸Kr	36	52	87.914447(14)	2.84(3) h	β⁻	⁸⁸Rb	0+
⁸⁹Kr	36	53	88.91763(6)	3.15(4) min	β⁻	⁸⁹Rb	3/2(+#)
⁹⁰Kr	36	54	89.919517(20)	32.32(9) s	β⁻	^90mRb	0+
⁹¹Kr	36	55	90.92345(6)	8.57(4) s	β⁻	⁹¹Rb	5/2(+)
⁹²Kr	36	56	91.926156(13)	1.840(8) s	β⁻ (99.96%)	⁹²Rb	0+
⁹²Kr	36	56	91.926156(13)	1.840(8) s	β⁻, n (.033%)	⁹¹Rb	0+
⁹³Kr	36	57	92.93127(11)	1.286(10) s	β⁻ (98.05%)	⁹³Rb	1/2+
⁹³Kr	36	57	92.93127(11)	1.286(10) s	β⁻, n (1.95%)	⁹²Rb	1/2+
⁹⁴Kr	36	58	93.93436(32)#	210(4) ms	β⁻ (94.3%)	⁹⁴Rb	0+
⁹⁴Kr	36	58	93.93436(32)#	210(4) ms	β⁻, n (5.7%)	⁹³Rb	0+
⁹⁵Kr	36	59	94.93984(43)#	114(3) ms	β⁻	⁹⁵Rb	1/2(+)
⁹⁶Kr	36	60	95.942998(62)	80(7) ms	β⁻	⁹⁶Rb	0+
⁹⁷Kr	36	61	96.94856(54)#	63(4) ms	β⁻	⁹⁷Rb	3/2+#
⁹⁷Kr	36	61	96.94856(54)#	63(4) ms	β⁻, n	⁹⁶Rb	3/2+#
⁹⁸Kr	36	62	97.95191(64)#	46(8) ms			0+
⁹⁹Kr	36	63	98.95760(64)#	40(11) ms			(3/2+)#
¹⁰⁰Kr	36	64	99.96114(54)#	10# ms [>300 ns]			0+
¹⁰¹Kr	36	65	unknown	>635 ns	β⁻, 2n	⁹⁹Rb	unknown
					β⁻, n	¹⁰⁰Rb
					β⁻	¹⁰¹Rb
¹⁰²Kr	36	66					0+
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The isotopic composition refers to that in air.

Notable isotopes

Krypton-81

Radioactive krypton-81 is the product of spallation reactions with cosmic rays striking gases present in the Earth atmosphere, along with the six stable or nearly stable krypton isotopes. Krypton-81 has a half-life of about 229,000 years.

Krypton-81 is used for dating ancient (50,000- to 800,000-year-old) groundwater and to determine their residence time in deep aquifers. One of the main technical limitations of the method is that it requires the sampling of very large volumes of water: several hundred liters or a few cubic meters of water. This is particularly challenging for dating pore water in deep clay aquitards with very low hydraulic conductivity.

Krypton-85

Krypton-85 is a radioisotope of krypton that has a half-life of about 10.75 years. This isotope is produced by the nuclear fission of uranium and plutonium in nuclear weapons testing and in nuclear reactors, as well as by cosmic rays. An important goal of the Limited Nuclear Test Ban Treaty of 1963 was to eliminate the release of such radioisotopes into the atmosphere, and since 1963 much of that krypton-85 has had time to decay. However, it is inevitable that krypton-85 is released during the reprocessing of fuel rods from nuclear reactors.

Atmospheric concentration

The atmospheric concentration of krypton-85 around the North Pole is about 30 percent higher than that at the Amundsen–Scott South Pole Station because nearly all of the world's nuclear reactors and all of its major nuclear reprocessing plants are located in the northern hemisphere, and also well-north of the equator. To be more specific, those nuclear reprocessing plants with significant capacities are located in the United States, the United Kingdom, the French Republic, the Russian Federation, Mainland China (PRC), Japan, India, and Pakistan.

Krypton-86

Krypton-86 was formerly used to define the meter from 1960 until 1983, when the definition of the meter was based on the wavelength of the 606 nm (orange) spectral line of a krypton-86 atom.

Others

All other radioisotopes of krypton have half-lives of less than one day, except for krypton-79, a positron emitter with a half-life of about 35.0 hours.

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

External links

Brookhaven National Laboratory: Krypton-101 information Archived 2017-10-18 at the Wayback Machine