Naturally occurring barium

Barium

Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...

(Ba) is a mix of six stable isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s and one very long-lived radioactive primordial isotope, barium-130, recently identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks). This nuclide decays by double-electron capture

Electron capture

Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...

 (absorbing two electrons and emitting two neutrinos) with a half-life of 70 trillion years (about 5,000 times the age of the universe).

There are a total of thirty-three known radioisotopes in addition to ¹³⁰Ba, but most of these are highly radioactive with half-lives

Half-life

Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 in the several millisecond to several minute range. and thus never encountered in nature. The only notable exceptions are ¹³³Ba which has a half-life of 10.51 years, and ^137mBa (2.55 minutes), which is the decay product of ¹³⁷Cs

Caesium-137

Caesium-137 is a radioactive isotope of caesium which is formed as a fission product by nuclear fission.It has a half-life of about 30.17 years, and decays by beta emission to a metastable nuclear isomer of barium-137: barium-137m . Caesium-137 is a radioactive isotope of caesium which is formed...

 (30.17 years, and a common fission product

Fission product

Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The...

).

Barium-114 is the lightest nuclide known to undergo cluster decay

Cluster decay

Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy...

, emitting a nucleus of stable ¹²C

Carbon-12

Carbon-12 is the more abundant of the two stable isotopes of the element carbon, accounting for 98.89% of carbon; it contains 6 protons, 6 neutrons, and 6 electrons....

 to produce ¹⁰²Sn in .0034% of decays.

Standard atomic mass: 137.327(7) u

Table

nuclide symbol	Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... )	N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... )	isotopic mass (u)	half-lifeBold for isotopes with half-lives longer than the age of the universe (nearly stable)	decay mode(s)Abbreviations: CD: Cluster decay Cluster decay Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy... EC: Electron capture Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....	daughter isotope(s)Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe Age of the universe The age of the universe is the time elapsed since the Big Bang posited by the most widely accepted scientific model of cosmology. The best current estimate of the age of the universe is 13.75 ± 0.13 billion years within the Lambda-CDM concordance model... )	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
114Ba	56	58	113.95068(15)	530(230) ms [0.43(+30−15) s]	β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... , p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very...  (99.59%)	113Xe	0+
					α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...  (.37%)	110Xe
					β+ (.04%)	114Cs
					CD Cluster decay Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy...  (.0034%)Lightest nuclide Nuclide A nuclide is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons Z, its number of neutrons N, and its nuclear energy state....  known to undergo cluster decay	102Sn, 12C Carbon-12 Carbon-12 is the more abundant of the two stable isotopes of the element carbon, accounting for 98.89% of carbon; it contains 6 protons, 6 neutrons, and 6 electrons....
115Ba	56	59	114.94737(64)#	0.45(5) s	β+	115Cs	(5/2+)#
					β+, p	114Xe
116Ba	56	60	115.94138(43)#	1.3(2) s	β+	116Cs	0+
					β+, p	115Xe
117Ba	56	61	116.93850(32)#	1.75(7) s	β+	117Cs	(3/2)(+#)
					β+, α	113I
					β+, p	116Xe
118Ba	56	62	117.93304(21)#	5.2(2) s	β+	118Cs	0+
					β+, p	117Xe
119Ba	56	63	118.93066(21)	5.4(3) s	β+	119Cs	(5/2+)
					β+, p	118Xe
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(+)
					β+, p (.02%)	120Xe
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(+)
124Ba	56	68	123.915094(13)	11.0(5) min	β+	124Cs	0+
125Ba	56	69	124.914473(12)	3.5(4) min	β+	125Cs	1/2(+#)
126Ba	56	70	125.911250(13)	100(2) min	β+	126Cs	0+
127Ba	56	71	126.911094(12)	12.7(4) min	β+	127Cs	1/2+
127mBa	80.33(12) keV			1.9(2) s	IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....	127Ba	7/2−
128Ba	56	72	127.908318(11)	2.43(5) d	β+	128Cs	0+
129Ba	56	73	128.908679(12)	2.23(11) h	β+	129Cs	1/2+
129mBa	8.42(6) keV			2.16(2) h	β+	129Cs	7/2+#
					IT	129Ba
130BaPrimordial radioisotope	56	74	129.9063208(30)	7×1013 a	Double EC Double electron capture Double electron capture is a decay mode of atomic nucleus. For a nuclide with number of nucleons A and atomic number Z, double electron capture is only possible if the mass of the nuclide of is lower....	130Xe	0+	0.00106(1)
130mBa	2475.12(18) keV			9.54(14) ms	IT	130Ba	8−
131Ba	56	75	130.906941(3)	11.50(6) d	β+	131Cs	1/2+
131mBa	187.14(12) keV			14.6(2) min	IT	131Ba	9/2−
132Ba	56	76	131.9050613(11)	Observationally StableBelieved to undergo β+β+ decay to 132Xe with a half-life Half-life Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...  over 300×1018 years			0+	0.00101(1)
133Ba	56	77	132.9060075(11)	10.51(5) a	EC	133Cs	1/2+
133mBa	288.247(9) keV			38.9(1) h	IT (99.99%)	133Ba	11/2−
					EC (.0096%)	133Cs
134Ba	56	78	133.9045084(4)	Observationally StableTheoretically capable of spontaneous fission Spontaneous fission Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses...			0+	0.02417(18)
135Ba	56	79	134.9056886(4)	Observationally Stable			3/2+	0.06592(12)
135mBa	268.22(2) keV			28.7(2) h	IT	135Ba	11/2−
136Ba	56	80	135.9045759(4)	Observationally Stable			0+	0.07854(24)
136mBa	2030.466(18) keV			308.4(19) ms	IT	136Ba	7−
137Ba	56	81	136.9058274(5)	Observationally Stable			3/2+	0.11232(24)
137m1Ba	661.659(3) keV			2.552(1) min	IT	137Ba	11/2−
137m2Ba	2349.1(4) keV			0.59(10) µs			(17/2−)
138BaFission product Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The...	56	82	137.9052472(5)	Observationally Stable			0+	0.71698(42)
138mBa	2090.54(6) keV			800(100) ns			6+
139Ba	56	83	138.9088413(5)	83.06(28) min	β-	139La	7/2−
140Ba	56	84	139.910605(9)	12.752(3) d	β-	140La	0+
141Ba	56	85	140.914411(9)	18.27(7) min	β-	141La	3/2−
142Ba	56	86	141.916453(7)	10.6(2) min	β-	142La	0+
143Ba	56	87	142.920627(14)	14.5(3) s	β-	143La	5/2−
144Ba	56	88	143.922953(14)	11.5(2) s	β- (96.4%)	144La	0+
					β+ (3.59%)	144Cs
145Ba	56	89	144.92763(8)	4.31(16) s	β-	145La	5/2−
146Ba	56	90	145.93022(8)	2.22(7) s	β- (99.98%)	146La	0+
					β-, n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13... (.02%)	145La
147Ba	56	91	146.93495(22)#	0.893(1) s	β- (99.94%)	147La	(3/2+)
					β-, n (.06%)	146La
148Ba	56	92	147.93772(9)	0.612(17) s	β- (99.6%)	148La	0+
					β-, n (.4%)	147La
149Ba	56	93	148.94258(21)#	344(7) ms	β- (99.57%)	149La	3/2−#
					β-, n (.43%)	148La
150Ba	56	94	149.94568(43)#	300 ms	β-	150La	0+
					β-, n (rare)	149La
151Ba	56	95	150.95081(43)#	200# ms [>300 ns]	β-	151La	3/2−#
152Ba	56	96	151.95427(54)#	100# ms	β-	152La	0+
153Ba	56	97	152.95961(86)#	80# ms	β-	153La	5/2−#

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