Isotopes of barium

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Naturally occurring barium (Ba) is a mix of seven stable isotopes. There are twenty-two isotopes known, but most of these are highly radioactive and have half-lives in the several millisecond to several minute range. The only notable exceptions are ¹³³Ba which has a half-life of 10.51 years, and ^137mBa (2.55 minutes).

Standard atomic mass: 137.327(7) u

[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)
nuclide symbol	excitation energy			half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
¹¹⁴Ba	56	58	113.95068(15)	530(230) ms [0.43(+30-15) s]	0+
¹¹⁵Ba	56	59	114.94737(64)#	0.45(5) s	(5/2+)#
¹¹⁶Ba	56	60	115.94138(43)#	1.3(2) s	0+
¹¹⁷Ba	56	61	116.93850(32)#	1.75(7) s	(3/2)(+#)
¹¹⁸Ba	56	62	117.93304(21)#	5.2(2) s	0+
¹¹⁹Ba	56	63	118.93066(21)	5.4(3) s	(5/2+)
¹²⁰Ba	56	64	119.92604(32)	24(2) s	0+
¹²¹Ba	56	65	120.92405(15)	29.7(15) s	5/2(+)
¹²²Ba	56	66	121.91990(3)	1.95(15) min	0+
¹²³Ba	56	67	122.918781(13)	2.7(4) min	5/2(+)
¹²⁴Ba	56	68	123.915094(13)	11.0(5) min	0+
¹²⁵Ba	56	69	124.914473(12)	3.5(4) min	1/2(+#)
¹²⁶Ba	56	70	125.911250(13)	100(2) min	0+
¹²⁷Ba	56	71	126.911094(12)	12.7(4) min	1/2+
^127mBa	80.33(12) keV			1.9(2) s	7/2-
¹²⁸Ba	56	72	127.908318(11)	2.43(5) d	0+
¹²⁹Ba	56	73	128.908679(12)	2.23(11) h	1/2+
^129mBa	8.42(6) keV			2.16(2) h	7/2+#
¹³⁰Ba	56	74	129.9063208(30)	STABLE [>4.0E+21 a]	0+	0.00106(1)
^130mBa	2475.12(18) keV			9.54(14) ms	8-
¹³¹Ba	56	75	130.906941(3)	11.50(6) d	1/2+
^131mBa	187.14(12) keV			14.6(2) min	9/2-
¹³²Ba	56	76	131.9050613(11)	STABLE [>300E+18 a]	0+	0.00101(1)
¹³³Ba	56	77	132.9060075(11)	10.51(5) a	1/2+
^133mBa	288.247(9) keV			38.9(1) h	11/2-
¹³⁴Ba	56	78	133.9045084(4)	STABLE	0+	0.02417(18)
¹³⁵Ba	56	79	134.9056886(4)	STABLE	3/2+	0.06592(12)
^135mBa	268.22(2) keV			28.7(2) h	11/2-
¹³⁶Ba	56	80	135.9045759(4)	STABLE	0+	0.07854(24)
^136mBa	2030.466(18) keV			308.4(19) ms	7-
¹³⁷Ba	56	81	136.9058274(5)	STABLE	3/2+	0.11232(24)
^137m1Ba	661.659(3) keV			2.552(1) min	11/2-
^137m2Ba	2349.1(4) keV			0.59(10) µs	(17/2-)
¹³⁸Ba	56	82	137.9052472(5)	STABLE	0+	0.71698(42)
^138mBa	2090.54(6) keV			800(100) ns	6+
¹³⁹Ba	56	83	138.9088413(5)	83.06(28) min	7/2-
¹⁴⁰Ba	56	84	139.910605(9)	12.752(3) d	0+
¹⁴¹Ba	56	85	140.914411(9)	18.27(7) min	3/2-
¹⁴²Ba	56	86	141.916453(7)	10.6(2) min	0+
¹⁴³Ba	56	87	142.920627(14)	14.5(3) s	5/2-
¹⁴⁴Ba	56	88	143.922953(14)	11.5(2) s	0+
¹⁴⁵Ba	56	89	144.92763(8)	4.31(16) s	5/2-
¹⁴⁶Ba	56	90	145.93022(8)	2.22(7) s	0+
¹⁴⁷Ba	56	91	146.93495(22)#	0.893(1) s	(3/2+)
¹⁴⁸Ba	56	92	147.93772(9)	0.612(17) s	0+
¹⁴⁹Ba	56	93	148.94258(21)#	344(7) ms	3/2-#
¹⁵⁰Ba	56	94	149.94568(43)#	300 ms	0+
¹⁵¹Ba	56	95	150.95081(43)#	200# ms [>300 ns]	3/2-#
¹⁵²Ba	56	96	151.95427(54)#	100# ms	0+
¹⁵³Ba	56	97	152.95961(86)#	80# ms	5/2-#

[edit] Notes

Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
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.