Isotopes of barium

Naturally occurring barium (₅₆Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001,^[4]^[5] presumably decaying by double electron capture with a half-life of (0.5–2.7)×10²¹ years (about 10¹¹ times the age of the universe). The two measurements are discordant; the above reflects the total range, the value in the table below is a crude average.

Quick facts Main isotopes, Decay ...

With the total range of mass numbers known 114 to 154, there are thirty-three known radioisotopes in addition to ¹³⁰Ba. The longest-lived of these is ¹³³Ba, which has a half-life of 10.538 years; all others have half-lives shorter than two weeks. The longest-lived isomers are ^133mBa at 38.90 hours and ^135m1Ba at 28.11 hours. The analogous ^137m1Ba (half-life 2.552 minutes) occurs in the decay of the common fission product caesium-137.

Barium-114 is theorized to undergo cluster decay, emitting a nucleus of stable ¹²C to produce ¹⁰²Sn. This decay has not been observed, with only an upper limit on the branching ratio of such decay (0.0034%).

More information Nuclide, Z ...

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[6] ^{[n 2]}^{[n 3]}	Half-life^[1]	Decay mode^[1] ^{[n 4]}	Daughter isotope ^{[n 5]}^{[n 6]}	Spin and parity^[1] ^{[n 7]}^{[n 8]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy			Half-life^[1]	Decay mode^[1] ^{[n 4]}	Daughter isotope ^{[n 5]}^{[n 6]}	Spin and parity^[1] ^{[n 7]}^{[n 8]}	Normal proportion^[1]	Range of variation
¹¹⁴Ba	56	58	113.95072(11)	460(125) ms	β⁺ (79%)	¹¹⁴Cs	0+
					α (0.9%)	¹¹⁰Xe
					β⁺, p (20%)	¹¹³Xe
					CD (<.0034%)	¹⁰²Sn, ¹²C
¹¹⁵Ba	56	59	114.94748(22)#	0.45(5) s	β⁺	¹¹⁵Cs	5/2+#
¹¹⁵Ba	56	59	114.94748(22)#	0.45(5) s	β⁺, p (>15%)	¹¹⁴Xe	5/2+#
¹¹⁶Ba	56	60	115.94162(22)#	1.3(2) s	β⁺ (97%)	¹¹⁶Cs	0+
¹¹⁶Ba	56	60	115.94162(22)#	1.3(2) s	β⁺, p (3%)	¹¹⁵Xe	0+
¹¹⁷Ba	56	61	116.93832(27)	1.75(7) s	β⁺ (87%)	¹¹⁷Cs	(3/2+)
					β⁺, p (13%)	¹¹⁶Xe
					β⁺, α (0.024%)	¹¹³I
¹¹⁸Ba	56	62	117.93323(22)#	5.2(2) s	β⁺	¹¹⁸Cs	0+
¹¹⁹Ba	56	63	118.93066(21)	5.4(3) s	β⁺ (75%)	¹¹⁹Cs	(3/2+)^[7]
¹¹⁹Ba	56	63	118.93066(21)	5.4(3) s	β⁺, p (25%)	¹¹⁸Xe	(3/2+)^[7]
^119mBa^[7]	66.0 keV			360(20) ns	IT	¹¹⁹Ba	(5/2−)
¹²⁰Ba	56	64	119.92604(32)	24(2) s	β⁺	¹²⁰Cs	0+
¹²¹Ba	56	65	120.92405(15)	29.7(15) s	β⁺ (99.98%)	¹²¹Cs	5/2+
¹²¹Ba	56	65	120.92405(15)	29.7(15) s	β⁺, p (0.02%)	¹²⁰Xe	5/2+
¹²²Ba	56	66	121.91990(3)	1.95(15) min	β⁺	¹²²Cs	0+
¹²³Ba	56	67	122.918781(13)	2.7(4) min	β⁺	¹²³Cs	5/2+
^123mBa	120.95(8) keV			830(60) ns	IT	¹²³Ba	1/2+#
¹²⁴Ba	56	68	123.915094(13)	11.0(5) min	β⁺	¹²⁴Cs	0+
¹²⁵Ba	56	69	124.914472(12)	3.3(3) min	β⁺	¹²⁵Cs	1/2+
^125mBa	120(20)# keV			2.76(14) μs	IT	¹²⁵Ba	(7/2−)
¹²⁶Ba	56	70	125.911250(13)	100(2) min	β⁺	¹²⁶Cs	0+
¹²⁷Ba	56	71	126.911091(12)	12.7(4) min	β⁺	¹²⁷Cs	1/2+
^127mBa	80.32(11) keV			1.93(7) s	IT	¹²⁷Ba	7/2−
¹²⁸Ba	56	72	127.9083524(17)	2.43(5) d	EC	¹²⁸Cs	0+
¹²⁹Ba	56	73	128.908683(11)	2.23(11) h	β⁺	¹²⁹Cs	1/2+
^129mBa	8.42(6) keV			2.135(10) h	β⁺	¹²⁹Cs	7/2+
^129mBa	8.42(6) keV			2.135(10) h	IT?	¹²⁹Ba	7/2+
¹³⁰Ba^{[n 9]}	56	74	129.9063260(3)	≈ 1×10²¹ y	β⁺β⁺	¹³⁰Xe	0+	0.0011(1)
^130mBa	2475.12(18) keV			9.54(14) ms	IT	¹³⁰Ba	8−
¹³¹Ba	56	75	130.9069463(4)	11.52(1) d	β⁺	¹³¹Cs	1/2+
^131mBa	187.995(9) keV			14.26(9) min	IT	¹³¹Ba	9/2−
¹³²Ba	56	76	131.9050612(11)	Observationally Stable^{[n 10]}			0+	0.0010(1)
¹³³Ba	56	77	132.9060074(11)	10.5379(16) y	EC	¹³³Cs	1/2+
^133mBa	288.252(9) keV			38.90(6) h	IT (99.99%)	¹³³Ba	11/2−
^133mBa	288.252(9) keV			38.90(6) h	EC (0.0104%)	¹³³Cs	11/2−
¹³⁴Ba^{[n 11]}	56	78	133.90450825(27)	Stable			0+	0.0242(15)
^134mBa	2957.2(5) keV			2.61(13) μs	IT	¹³⁴Ba	10+
¹³⁵Ba	56	79	134.90568845(26)	Stable			3/2+	0.0659(10)
^135m1Ba	268.218(20) keV			28.11(2) h	IT	¹³⁵Ba	11/2−
^135m2Ba	2388.0(5) keV			1.06(4) ms	IT	¹³⁵Ba	(23/2+)
¹³⁶Ba	56	80	135.90457580(26)	Stable			0+	0.0785(24)
^136m1Ba	2030.535(18) keV			308.4(19) ms	IT	¹³⁶Ba	7−
^136m2Ba	3357.19(25) keV			91(2) ns	IT	¹³⁶Ba	10+
¹³⁷Ba^{[n 11]}	56	81	136.90582721(27)	Stable			3/2+	0.1123(23)
^137m1Ba^{[n 11]}	661.659(3) keV			2.552(1) min	IT	¹³⁷Ba	11/2−
^137m2Ba	2349.1(5) keV			589(20) ns	IT	¹³⁷Ba	(19/2−)
¹³⁸Ba^{[n 11]}	56	82	137.90524706(27)	Stable			0+	0.7170(29)
^138mBa	2090.536(21) keV			850(100) ns	IT	¹³⁸Ba	6+
¹³⁹Ba^{[n 11]}	56	83	138.90884116(27)	82.93(9) min	β⁻	¹³⁹La	7/2−
¹⁴⁰Ba^{[n 11]}	56	84	139.910608(8)	12.7534(21) d	β⁻	¹⁴⁰La	0+
¹⁴¹Ba	56	85	140.914404(6)	18.27(7) min	β⁻	¹⁴¹La	3/2−
¹⁴²Ba	56	86	141.916433(6)	10.6(2) min	β⁻	¹⁴²La	0+
¹⁴³Ba	56	87	142.920625(7)	14.5(3) s	β⁻	¹⁴³La	5/2−
¹⁴⁴Ba	56	88	143.922955(8)	11.73(8) s	β⁻	¹⁴⁴La	0+
¹⁴⁵Ba	56	89	144.927518(9)	4.31(16) s	β⁻	¹⁴⁵La	5/2−
¹⁴⁶Ba	56	90	145.9303632(19)	2.15(4) s	β⁻	¹⁴⁶La	0+
¹⁴⁷Ba	56	91	146.935304(21)	893(1) ms	β⁻ (99.93%)	¹⁴⁷La	5/2−
¹⁴⁷Ba	56	91	146.935304(21)	893(1) ms	β⁻, n (0.07%)	¹⁴⁶La	5/2−
¹⁴⁸Ba	56	92	147.9382230(16)	620(5) ms	β⁻ (99.6%)	¹⁴⁸La	0+
¹⁴⁸Ba	56	92	147.9382230(16)	620(5) ms	β⁻, n (0.4%)	¹⁴⁷La	0+
¹⁴⁹Ba	56	93	148.9432840(27)	349(4) ms	β⁻ (96.1%)	¹⁴⁹La	3/2−#
¹⁴⁹Ba	56	93	148.9432840(27)	349(4) ms	β⁻, n (3.9%)	¹⁴⁸La	3/2−#
¹⁵⁰Ba	56	94	149.946441(6)	258(5) ms	β⁻ (99.0%)	¹⁵⁰La	0+
¹⁵⁰Ba	56	94	149.946441(6)	258(5) ms	β⁻, n (1.0%)	¹⁴⁹La	0+
¹⁵¹Ba	56	95	150.95176(43)#	167(5) ms	β⁻	¹⁵¹La	3/2−#
¹⁵¹Ba	56	95	150.95176(43)#	167(5) ms	β⁻, n?	¹⁵⁰La	3/2−#
¹⁵²Ba	56	96	151.95533(43)#	139(8) ms	β⁻	¹⁵²La	0+
¹⁵²Ba	56	96	151.95533(43)#	139(8) ms	β⁻, n?	¹⁵¹La	0+
¹⁵³Ba	56	97	152.96085(43)#	113(39) ms	β⁻	¹⁵³La	5/2−#
					β⁻, n?	¹⁵²La
					β⁻, 2n?	¹⁵¹La
¹⁵⁴Ba	56	98	153.96466(54)#	53(48) ms	β⁻	¹⁵⁴La	0+
This table header & footer: view

[n 1]
^mBa – Excited nuclear isomer.
[n 2]
( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
[n 3]
# – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
[n 4]
Modes of decay:

EC: Electron capture

CD: Cluster decay

IT: Isomeric transition

n: Neutron emission

p: Proton emission
[n 5]
Bold italics symbol as daughter – Daughter product is nearly stable.
[n 6]
Bold symbol as daughter – Daughter product is stable.
[n 7]
( ) spin value – Indicates spin with weak assignment arguments.
[n 8]
# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
[n 9]
Primordial radionuclide
[N 10]
Believed to undergo β⁺β⁺ decay to ¹³²Xe with a half-life over 3×10²⁰ years
[N 11]
Fission product

Isotopes of barium

List of isotopes

See also

References

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