Isotopes of radium

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Radium (Ra) has no stable isotopes. A standard atomic mass cannot be given.

Isotopes of radium occurring within the radioactive disintegration chains of actinium and thorium were known as

• actinium X, ²²³Ra
• thorium X, ²²⁴Ra
• mesothorium I, ²²⁸Ra

[edit] Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
202Ra	88	114	202.00989(7)	2.6(21) ms [0.7(+33-3) ms]	0+
203Ra	88	115	203.00927(9)	4(3) ms	(3/2-)
203mRa	220(90) keV			41(17) ms	(13/2+)
204Ra	88	116	204.006500(17)	60(11) ms [59(+12-9) ms]	0+
205Ra	88	117	205.00627(9)	220(40) ms [210(+60-40) ms]	(3/2-)
205mRa	310(110)# keV			180(50) ms [170(+60-40) ms]	(13/2+)
206Ra	88	118	206.003827(19)	0.24(2) s	0+
207Ra	88	119	207.00380(6)	1.3(2) s	(5/2-,3/2-)
207mRa	560(50) keV			57(8) ms	(13/2+)
208Ra	88	120	208.001840(17)	1.3(2) s	0+
208mRa	1800(200) keV			270 ns	(8+)
209Ra	88	121	209.00199(5)	4.6(2) s	5/2-
210Ra	88	122	210.000495(16)	3.7(2) s	0+
210mRa	1800(200) keV			2.24 µs	(8+)
211Ra	88	123	211.000898(28)	13(2) s	5/2(-)
212Ra	88	124	211.999794(12)	13.0(2) s	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	1/2-
213mRa	1769(6) keV			2.1(1) ms	17/2-#
214Ra	88	126	214.000108(10)	2.46(3) s	0+
215Ra	88	127	215.002720(8)	1.55(7) ms	(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	0+
217Ra	88	129	217.006320(9)	1.63(17) µs	(9/2+)
218Ra	88	130	218.007140(12)	25.2(3) µs	0+
219Ra	88	131	219.010085(9)	10(3) ms	(7/2)+
220Ra	88	132	220.011028(10)	17.9(14) ms	0+
221Ra	88	133	221.013917(5)	28(2) s	5/2+
222Ra	88	134	222.015375(5)	38.0(5) s	0+
223Ra	88	135	223.0185022(27)	11.43(5) d	3/2+
224Ra	88	136	224.0202118(24)	3.6319(23) d	0+
225Ra	88	137	225.023612(3)	14.9(2) d	1/2+
226Ra	88	138	226.0254098(25)	1600(7) a	0+
227Ra	88	139	227.0291778(25)	42.2(5) min	3/2+
228Ra	88	140	228.0310703(26)	5.75(3) a	0+
229Ra	88	141	229.034958(20)	4.0(2) min	5/2(+)
230Ra	88	142	230.037056(13)	93(2) min	0+
231Ra	88	143	231.04122(32)#	103(3) s	(5/2+)
231mRa	66.21(9) keV			~53 µs	(1/2+)
232Ra	88	144	232.04364(30)#	250(50) s	0+
233Ra	88	145	233.04806(50)#	30(5) s	1/2+#
234Ra	88	146	234.05070(53)#	30(10) s	0+

[edit] Notes

• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

[edit] References

• Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
• Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
• Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
  • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
  • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
  • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.

Isotopes of francium	Isotopes of radium	Isotopes of actinium
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