Isotopes of radium

Radium (₈₈Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is ²²⁶Ra with a half-life of 1600 years. ²²⁶Ra occurs in the decay chain of ²³⁸U (often referred to as the radium series). Radium has 34 known isotopes from ²⁰¹Ra to ²³⁴Ra.

In 2013 it was discovered that the nucleus of radium-224 is pear-shaped.^[2] This was the first discovery of an asymmetrical nucleus.

List of isotopes

Nuclide ^{[n 1]}	Historic name	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life	Decay mode ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity ^{[n 6]}^{[n 7]}	Isotopic abundance
Nuclide ^{[n 1]}	Historic name	Excitation energy^{[n 7]}			Half-life	Decay mode ^{[n 4]}	Daughter isotope ^{[n 5]}	Spin and parity ^{[n 6]}^{[n 7]}	Isotopic abundance
²⁰¹Ra^[3]		88	113		8+40 −4 ms	α	¹⁹⁷Rn	(3/2−)
^201mRa^[4]		260(30) keV			1.6+7.7 −0.7 ms	α	^197mRn	(13/2+)
²⁰²Ra		88	114	202.00989(7)	3.8+1.3 −0.8 ms^[3]	α	¹⁹⁸Rn	0+
²⁰³Ra		88	115	203.00927(9)	4(3) ms	α	¹⁹⁹Rn	(3/2−)
²⁰³Ra		88	115	203.00927(9)	4(3) ms	β⁺ (rare)	²⁰³Fr	(3/2−)
^203mRa		220(90) keV			41(17) ms	α	¹⁹⁹Rn	(13/2+)
^203mRa		220(90) keV			41(17) ms	β⁺ (rare)	²⁰³Fr	(13/2+)
²⁰⁴Ra		88	116	204.006500(17)	60(11) ms [59(+12−9) ms]	α (99.7%)	²⁰⁰Rn	0+
²⁰⁴Ra		88	116	204.006500(17)	60(11) ms [59(+12−9) ms]	β⁺ (.3%)	²⁰⁴Fr	0+
²⁰⁵Ra		88	117	205.00627(9)	220(40) ms [210(+60−40) ms]	α	²⁰¹Rn	(3/2−)
²⁰⁵Ra		88	117	205.00627(9)	220(40) ms [210(+60−40) ms]	β⁺ (rare)	²⁰⁵Fr	(3/2−)
^205mRa		310(110)# keV			180(50) ms [170(+60−40) ms]	α	²⁰¹Rn	(13/2+)
^205mRa		310(110)# keV			180(50) ms [170(+60−40) ms]	IT (rare)	²⁰⁵Ra	(13/2+)
²⁰⁶Ra		88	118	206.003827(19)	0.24(2) s	α	²⁰²Rn	0+
²⁰⁷Ra		88	119	207.00380(6)	1.3(2) s	α (90%)	²⁰³Rn	(5/2−, 3/2−)
²⁰⁷Ra		88	119	207.00380(6)	1.3(2) s	β⁺ (10%)	²⁰⁷Fr	(5/2−, 3/2−)
^207mRa		560(50) keV			57(8) ms	IT (85%)	²⁰⁷Ra	(13/2+)
						α (15%)	²⁰³Rn
						β⁺ (.55%)	²⁰⁷Fr
²⁰⁸Ra		88	120	208.001840(17)	1.3(2) s	α (95%)	²⁰⁴Rn	0+
²⁰⁸Ra		88	120	208.001840(17)	1.3(2) s	β⁺ (5%)	²⁰⁸Fr	0+
^208mRa		1800(200) keV			270 ns			(8+)
²⁰⁹Ra		88	121	209.00199(5)	4.6(2) s	α (90%)	²⁰⁵Rn	5/2−
²⁰⁹Ra		88	121	209.00199(5)	4.6(2) s	β⁺ (10%)	²⁰⁹Fr	5/2−
²¹⁰Ra		88	122	210.000495(16)	3.7(2) s	α (96%)	²⁰⁶Rn	0+
²¹⁰Ra		88	122	210.000495(16)	3.7(2) s	β⁺ (4%)	²¹⁰Fr	0+
^210mRa		1800(200) keV			2.24 μs			(8+)
²¹¹Ra		88	123	211.000898(28)	13(2) s	α (97%)	²⁰⁷Rn	5/2(−)
²¹¹Ra		88	123	211.000898(28)	13(2) s	β⁺ (3%)	²¹¹Fr	5/2(−)
²¹²Ra		88	124	211.999794(12)	13.0(2) s	α (85%)	²⁰⁸Rn	0+
²¹²Ra		88	124	211.999794(12)	13.0(2) s	β⁺ (15%)	²¹²Fr	0+
^212m1Ra		1958.4(5) keV			10.9(4) μs			(8)+
^212m2Ra		2613.4(5) keV			0.85(13) μs			(11)−
²¹³Ra		88	125	213.000384(22)	2.74(6) min	α (80%)	²⁰⁹Rn	1/2−
²¹³Ra		88	125	213.000384(22)	2.74(6) min	β⁺ (20%)	²¹³Fr	1/2−
^213mRa		1769(6) keV			2.1(1) ms	IT (99%)	²¹³Ra	17/2−#
^213mRa		1769(6) keV			2.1(1) ms	α (1%)	²⁰⁹Rn	17/2−#
²¹⁴Ra		88	126	214.000108(10)	2.46(3) s	α (99.94%)	²¹⁰Rn	0+
²¹⁴Ra		88	126	214.000108(10)	2.46(3) s	β⁺ (.06%)	²¹⁴Fr	0+
²¹⁵Ra		88	127	215.002720(8)	1.55(7) ms	α	²¹¹Rn	(9/2+)#
^215m1Ra		1877.8(5) keV			7.1(2) μs			(25/2+)
^215m2Ra		2246.9(5) keV			1.39(7) μs			(29/2−)
^215m3Ra		3756.6(6)+X keV			0.555(10) μs			(43/2−)
²¹⁶Ra		88	128	216.003533(9)	182(10) ns	α	²¹²Rn	0+
²¹⁶Ra		88	128	216.003533(9)	182(10) ns	EC (<1×10⁻⁸%)	²¹⁶Fr	0+
²¹⁷Ra		88	129	217.006320(9)	1.63(17) μs	α	²¹³Rn	(9/2+)
²¹⁸Ra		88	130	218.007140(12)	25.2(3) μs	α	²¹⁴Rn	0+
²¹⁹Ra		88	131	219.010085(9)	10(3) ms	α	²¹⁵Rn	(7/2)+
²²⁰Ra		88	132	220.011028(10)	17.9(14) ms	α	²¹⁶Rn	0+
²²¹Ra		88	133	221.013917(5)	28(2) s	α	²¹⁷Rn	5/2+	Trace^{[n 8]}
²²¹Ra		88	133	221.013917(5)	28(2) s	CD (1.2×10⁻¹⁰%)^{[n 9]}	²⁰⁷Pb ¹⁴C	5/2+	Trace^{[n 8]}
²²²Ra		88	134	222.015375(5)	38.0(5) s	α	²¹⁸Rn	0+
²²²Ra		88	134	222.015375(5)	38.0(5) s	CD (3×10⁻⁸%)	²⁰⁸Pb ¹⁴C	0+
²²³Ra^{[n 10]}	Actinium X	88	135	223.0185022(27)	11.43(5) d	α	²¹⁹Rn	3/2+	Trace^{[n 11]}
²²³Ra^{[n 10]}	Actinium X	88	135	223.0185022(27)	11.43(5) d	CD (6.4×10⁻⁸%)	²⁰⁹Pb ¹⁴C	3/2+	Trace^{[n 11]}
²²⁴Ra	Thorium X	88	136	224.0202118(24)	3.6319(23) d	α	²²⁰Rn	0+	Trace^{[n 12]}
²²⁴Ra	Thorium X	88	136	224.0202118(24)	3.6319(23) d	CD (4.3×10⁻⁹%)	²¹⁰Pb ¹⁴C	0+	Trace^{[n 12]}
²²⁵Ra		88	137	225.023612(3)	14.9(2) d	β⁻	²²⁵Ac	1/2+	Trace^{[n 13]}
²²⁵Ra		88	137	225.023612(3)	14.9(2) d	α (2.0×10⁻³%)^[5]	²²¹Rn	1/2+	Trace^{[n 13]}
²²⁶Ra	Radium^{[n 14]}	88	138	226.0254098(25)	1600(7) y	α^{[n 15]}	²²²Rn	0+	Trace^{[n 16]}
²²⁶Ra	Radium^{[n 14]}	88	138	226.0254098(25)	1600(7) y	CD (2.6×10⁻⁹%)	²¹²Pb ¹⁴C	0+	Trace^{[n 16]}
²²⁷Ra		88	139	227.0291778(25)	42.2(5) min	β⁻	²²⁷Ac	3/2+
²²⁸Ra	Mesothorium 1	88	140	228.0310703(26)	5.75(3) y	β⁻	²²⁸Ac	0+	Trace^{[n 12]}
²²⁹Ra		88	141	229.034958(20)	4.0(2) min	β⁻	²²⁹Ac	5/2(+)
²³⁰Ra		88	142	230.037056(13)	93(2) min	β⁻	²³⁰Ac	0+
²³¹Ra		88	143	231.04122(32)#	103(3) s	β⁻	²³¹Ac	(5/2+)
^231mRa		66.21(9) keV			~53 μs			(1/2+)
²³²Ra		88	144	232.04364(30)#	250(50) s	β⁻	²³²Ac	0+
²³³Ra		88	145	233.04806(50)#	30(5) s	β⁻	²³³Ac	1/2+#
²³⁴Ra		88	146	234.05070(53)#	30(10) s	β⁻	²³⁴Ac	0+
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Actinides vs fission products

Actinides and fission products by half-life v t e
Actinides^[6] by decay chain				Half-life range (a)	Fission products of ²³⁵U by yield^[7]
4n	4n + 1	4n + 2	4n + 3	Half-life range (a)	4.5–7%	0.04–1.25%	<0.001%
²²⁸Ra^№				4–6 a		¹⁵⁵Eu^þ
²⁴⁴Cm^ƒ	²⁴¹Pu^ƒ	²⁵⁰Cf	²²⁷Ac^№	10–29 a	⁹⁰Sr	⁸⁵Kr	^113mCd^þ
²³²U^ƒ		²³⁸Pu^ƒ	²⁴³Cm^ƒ	29–97 a	¹³⁷Cs	¹⁵¹Sm^þ	^121mSn
²⁴⁸Bk^[8]	²⁴⁹Cf^ƒ	^242mAm^ƒ		141–351 a	No fission products have a half-life in the range of 100 a–210 ka ...
	²⁴¹Am^ƒ		²⁵¹Cf^ƒ^[9]	430–900 a
		²²⁶Ra^№	²⁴⁷Bk	1.3–1.6 ka
²⁴⁰Pu	²²⁹Th	²⁴⁶Cm^ƒ	²⁴³Am^ƒ	4.7–7.4 ka
	²⁴⁵Cm^ƒ	²⁵⁰Cm		8.3–8.5 ka
			²³⁹Pu^ƒ	24.1 ka
		²³⁰Th^№	²³¹Pa^№	32–76 ka
²³⁶Np^ƒ	²³³U^ƒ	²³⁴U^№		150–250 ka	⁹⁹Tc^₡	¹²⁶Sn
²⁴⁸Cm		²⁴²Pu		327–375 ka		⁷⁹Se^₡
				1.53 Ma	⁹³Zr
	²³⁷Np^ƒ			2.1–6.5 Ma	¹³⁵Cs^₡	¹⁰⁷Pd
²³⁶U			²⁴⁷Cm^ƒ	15–24 Ma		¹²⁹I^₡
²⁴⁴Pu				80 Ma	... nor beyond 15.7 Ma^[10]
²³²Th^№		²³⁸U^№	²³⁵U^ƒ№	0.7–14.1 Ga	... nor beyond 15.7 Ma^[10]
₡, has thermal neutron capture cross section in the range of 8–50 barns ƒ, fissile №, primarily a naturally occurring radioactive material (NORM) þ, neutron poison (thermal neutron capture cross section greater than 3k barns)

References

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
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.

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