Isotopes of caesium
List of isotopes
Abbreviations: EC: Electron capture IT: Isomeric transition Bold for stable isotopes, bold italics for near-stable isotopes (half-life longer than the age of the universe) Used to define the second Fission product

Isotopes of caesium

Section Title: List of isotopes
Table Section Text: Abbreviations: EC: Electron capture IT: Isomeric transition Bold for stable isotopes, bold italics for near-stable isotopes (half-life longer than the age of the universe) Used to define the second Fission product

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)	daughter isotope(s)	nuclear spin and parity	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)

excitation energy

112Cs	55	57	111.95030(33)#	500(100) µs	p	111Xe	1+#

α	108I

113Cs	55	58	112.94449(11)	16.7(7) µs	p (99.97%)	112Xe	5/2+#

β+ (.03%)	113Xe

114Cs	55	59	113.94145(33)#	0.57(2) s	β+ (91.09%)	114Xe	(1+)

β+, p (8.69%)	113I

β+, α (.19%)	110Te

α (.018%)	110I

115Cs	55	60	114.93591(32)#	1.4(8) s	β+ (99.93%)	115Xe	9/2+#

β+, p (.07%)	114I

116Cs	55	61	115.93337(11)#	0.70(4) s	β+ (99.67%)	116Xe	(1+)

β+, p (.279%)	115I

β+, α (.049%)	112Te

116mCs	100(60)# keV	3.85(13) s	β+ (99.48%)	116Xe	4+,5,6

β+, p (.51%)	115I

β+, α (.008%)	112Te

117Cs	55	62	116.92867(7)	8.4(6) s	β+	117Xe	(9/2+)#

117mCs	150(80)# keV	6.5(4) s	β+	117Xe	3/2+#

118Cs	55	63	117.926559(14)	14(2) s	β+ (99.95%)	118Xe	2

β+, p (.042%)	117I

β+, α (.0024%)	114Te

118mCs	100(60)# keV	17(3) s	β+ (99.95%)	118Xe	(7−)

β+, p (.042%)	117I

β+, α (.0024%)	114Te

119Cs	55	64	118.922377(15)	43.0(2) s	β+	119Xe	9/2+

β+, α (2×10−6%)	115Te

119mCs	50(30)# keV	30.4(1) s	β+	119Xe	3/2(+)

120Cs	55	65	119.920677(11)	61.2(18) s	β+	120Xe	2(−#)

β+, α (2×10−5%)	116Te

β+, p (7×10−6%)	118I

120mCs	100(60)# keV	57(6) s	β+	120Xe	(7−)

β+, α (2×10−5%)	116Te

β+, p (7×10−6%)	118I

121Cs	55	66	120.917229(15)	155(4) s	β+	121Xe	3/2(+)

121mCs	68.5(3) keV	122(3) s	β+ (83%)	121Xe	9/2(+)

IT (17%)	121Cs

122Cs	55	67	121.91611(3)	21.18(19) s	β+	122Xe	1+

β+, α (2×10−7%)	118Te

122m1Cs	45.8 keV	>1 µs	(3)+

122m2Cs	140(30) keV	3.70(11) min	β+	122Xe	8−

122m3Cs	127.0(5) keV	360(20) ms	(5)−

123Cs	55	68	122.912996(13)	5.88(3) min	β+	123Xe	1/2+

123m1Cs	156.27(5) keV	1.64(12) s	IT	123Cs	(11/2)−

123m2Cs	231.63+X keV	114(5) ns	(9/2+)

124Cs	55	69	123.912258(9)	30.9(4) s	β+	124Xe	1+

124mCs	462.55(17) keV	6.3(2) s	IT	124Cs	(7)+

125Cs	55	70	124.909728(8)	46.7(1) min	β+	125Xe	1/2(+)

125mCs	266.6(11) keV	900(30) ms	(11/2−)

126Cs	55	71	125.909452(13)	1.64(2) min	β+	126Xe	1+

126m1Cs	273.0(7) keV	>1 µs

126m2Cs	596.1(11) keV	171(14) µs

127Cs	55	72	126.907418(6)	6.25(10) h	β+	127Xe	1/2+

127mCs	452.23(21) keV	55(3) µs	(11/2)−

128Cs	55	73	127.907749(6)	3.640(14) min	β+	128Xe	1+

129Cs	55	74	128.906064(5)	32.06(6) h	β+	129Xe	1/2+

130Cs	55	75	129.906709(9)	29.21(4) min	β+ (98.4%)	130Xe	1+

β− (1.6%)	130Ba

130mCs	163.25(11) keV	3.46(6) min	IT (99.83%)	130Cs	5−

β+ (.16%)	130Xe

131Cs	55	76	130.905464(5)	9.689(16) d	EC	131Xe	5/2+

132Cs	55	77	131.9064343(20)	6.480(6) d	β+ (98.13%)	132Xe	2+

β− (1.87%)	132Ba

133Cs	55	78	132.905451933(24)	Stable	7/2+	1.0000

134Cs	55	79	133.906718475(28)	2.0652(4) y	β−	134Ba	4+

EC (3×10−4%)	134Xe

134mCs	138.7441(26) keV	2.912(2) h	IT	134Cs	8−

135Cs	55	80	134.9059770(11)	2.3 x106 y	β−	135Ba	7/2+

135mCs	1632.9(15) keV	53(2) min	IT	135Cs	19/2−

136Cs	55	81	135.9073116(20)	13.16(3) d	β−	136Ba	5+

136mCs	518(5) keV	19(2) s	β−	136Ba	8−

IT	136Cs

137Cs	55	82	136.9070895(5)	30.1671(13) y	β− (95%)	137mBa	7/2+

β− (5%)	137Ba

138Cs	55	83	137.911017(10)	33.41(18) min	β−	138Ba	3−

138mCs	79.9(3) keV	2.91(8) min	IT (81%)	138Cs	6−

β− (19%)	138Ba

139Cs	55	84	138.913364(3)	9.27(5) min	β−	139Ba	7/2+

140Cs	55	85	139.917282(9)	63.7(3) s	β−	140Ba	1−

141Cs	55	86	140.920046(11)	24.84(16) s	β− (99.96%)	141Ba	7/2+

β−, n (.0349%)	140Ba

142Cs	55	87	141.924299(11)	1.689(11) s	β− (99.9%)	142Ba	0−

β−, n (.091%)	141Ba

143Cs	55	88	142.927352(25)	1.791(7) s	β− (98.38%)	143Ba	3/2+

β−, n (1.62%)	142Ba

144Cs	55	89	143.932077(28)	994(4) ms	β− (96.8%)	144Ba	1(−#)

β−, n (3.2%)	143Ba

144mCs	300(200)# keV	<1 s	β−	144Ba	(>3)

IT	144Cs

145Cs	55	90	144.935526(12)	582(6) ms	β− (85.7%)	145Ba	3/2+

β−, n (14.3%)	144Ba

146Cs	55	91	145.94029(8)	0.321(2) s	β− (85.8%)	146Ba	1−

β−, n (14.2%)	145Ba

147Cs	55	92	146.94416(6)	0.235(3) s	β− (71.5%)	147Ba	(3/2+)

β−, n (28.49%)	147Ba

148Cs	55	93	147.94922(62)	146(6) ms	β− (74.9%)	148Ba

β−, n (25.1%)	147Ba

149Cs	55	94	148.95293(21)#	150# ms [>50 ms]	β−	149Ba	3/2+#

β−, n	148Ba

150Cs	55	95	149.95817(32)#	100# ms [>50 ms]	β−	150Ba

β−, n	149Ba

151Cs	55	96	150.96219(54)#	60# ms [>50 ms]	β−	151Ba	3/2+#

β−, n	150Ba

Sentence(s)

Isotope ¹³³Cs is stable.

final_sentence: Isotope ¹³³Cs is stable.