Isotopes of samarium
List of isotopes
Bold for isotopes with half-lives longer than the age of the universe (nearly stable) Abbreviations: EC: Electron capture IT: Isomeric transition Bold for stable isotopes, bold italics for nearly stable isotopes (half-life longer than the age of the universe) Believed to undergo β⁺β⁺ decay to ¹⁴⁴Nd Primordial radioisotope Fission product Used in Samarium–neodymium dating Neutron poison in reactors Believed to undergo α decay to ¹⁴⁵Nd with a half-life over 2×10¹⁵ years Believed to undergo α decay to ¹⁴⁶Nd Believed to undergo α decay to ¹⁴⁸Nd Believed to undergo β−β− decay to ¹⁵⁴Gd with a half-life over 2.3×10¹⁸ years

Isotopes of samarium

Section Title: List of isotopes
Table Section Text: Bold for isotopes with half-lives longer than the age of the universe (nearly stable) Abbreviations: EC: Electron capture IT: Isomeric transition Bold for stable isotopes, bold italics for nearly stable isotopes (half-life longer than the age of the universe) Believed to undergo β⁺β⁺ decay to ¹⁴⁴Nd Primordial radioisotope Fission product Used in Samarium–neodymium dating Neutron poison in reactors Believed to undergo α decay to ¹⁴⁵Nd with a half-life over 2×10¹⁵ years Believed to undergo α decay to ¹⁴⁶Nd Believed to undergo α decay to ¹⁴⁸Nd Believed to undergo β−β− decay to ¹⁵⁴Gd with a half-life over 2.3×10¹⁸ years

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

128Sm	62	66	127.95808(54)#	0.5# s	0+

129Sm	62	67	128.95464(54)#	550(100) ms	5/2+#

130Sm	62	68	129.94892(43)#	1# s	β+	130Pm	0+

131Sm	62	69	130.94611(32)#	1.2(2) s	β+	131Pm	5/2+#

β+, p (rare)	130Nd

132Sm	62	70	131.94069(32)#	4.0(3) s	β+	132Pm	0+

β+, p	131Nd

133Sm	62	71	132.93867(21)#	2.90(17) s	β+	133Pm	(5/2+)

β+, p	132Nd

134Sm	62	72	133.93397(21)#	10(1) s	β+	134Pm	0+

135Sm	62	73	134.93252(17)	10.3(5) s	β+ (99.98%)	135Pm	(7/2+)

β+, p (.02%)	134Nd

135mSm	0(300)# keV	2.4(9) s	β+	135Pm	(3/2+,5/2+)

136Sm	62	74	135.928276(13)	47(2) s	β+	136Pm	0+

136mSm	2264.7(11) keV	15(1) µs	(8−)

137Sm	62	75	136.92697(5)	45(1) s	β+	137Pm	(9/2−)

137mSm	180(50)# keV	20# s	β+	137Pm	1/2+#

138Sm	62	76	137.923244(13)	3.1(2) min	β+	138Pm	0+

139Sm	62	77	138.922297(12)	2.57(10) min	β+	139Pm	1/2+

139mSm	457.40(22) keV	10.7(6) s	IT (93.7%)	139Sm	11/2−

β+ (6.3%)	139Pm

140Sm	62	78	139.918995(13)	14.82(12) min	β+	140Pm	0+

141Sm	62	79	140.918476(9)	10.2(2) min	β+	141Pm	1/2+

141mSm	176.0(3) keV	22.6(2) min	β+ (99.69%)	141Pm	11/2−

IT (.31%)	141Sm

142Sm	62	80	141.915198(6)	72.49(5) min	β+	142Pm	0+

143Sm	62	81	142.914628(4)	8.75(8) min	β+	143Pm	3/2+

143m1Sm	753.99(16) keV	66(2) s	IT (99.76%)	143Sm	11/2−

β+ (.24%)	143Pm

143m2Sm	2793.8(13) keV	30(3) ms	23/2(−)

144Sm	62	82	143.911999(3)	Observationally Stable	0+	0.0307(7)

144mSm	2323.60(8) keV	880(25) ns	6+

145Sm	62	83	144.913410(3)	340(3) d	EC	145Pm	7/2−

145mSm	8786.2(7) keV	990(170) ns [0.96(+19−15) µs]	(49/2+)

146Sm	62	84	145.913041(4)	6.8(7)×107 y	α	142Nd	0+	Trace

147Sm	62	85	146.9148979(26)	1.06(2)×1011 y	α	143Nd	7/2−	0.1499(18)

148Sm	62	86	147.9148227(26)	7(3)×1015 y	α	144Nd	0+	0.1124(10)

149Sm	62	87	148.9171847(26)	Observationally Stable	7/2−	0.1382(7)

150Sm	62	88	149.9172755(26)	Observationally Stable	0+	0.0738(1)

151Sm	62	89	150.9199324(26)	88.8(24) y	β−	151Eu	5/2−

151mSm	261.13(4) keV	1.4(1) µs	(11/2)−

152Sm	62	90	151.9197324(27)	Observationally Stable	0+	0.2675(16)

153Sm	62	91	152.9220974(27)	46.284(4) h	β−	153Eu	3/2+

153mSm	98.37(10) keV	10.6(3) ms	IT	153Sm	11/2−

154Sm	62	92	153.9222093(27)	Observationally Stable	0+	0.2275(29)

155Sm	62	93	154.9246402(28)	22.3(2) min	β−	155Eu	3/2−

156Sm	62	94	155.925528(10)	9.4(2) h	β−	156Eu	0+

156mSm	1397.55(9) keV	185(7) ns	5−

157Sm	62	95	156.92836(5)	8.03(7) min	β−	157Eu	(3/2−)

158Sm	62	96	157.92999(8)	5.30(3) min	β−	158Eu	0+

159Sm	62	97	158.93321(11)	11.37(15) s	β−	159Eu	5/2−

160Sm	62	98	159.93514(21)#	9.6(3) s	β−	160Eu	0+

161Sm	62	99	160.93883(32)#	4.8(8) s	β−	161Eu	7/2+#

162Sm	62	100	161.94122(54)#	2.4(5) s	β−	162Eu	0+

163Sm	62	101	162.94536(75)#	1# s	β−	163Eu	1/2−#

164Sm	62	102	163.94828(86)#	500# ms	β−	164Eu	0+

165Sm	62	103	164.95298(97)#	200# ms	β−	165Eu	5/2−#

Sentence(s)

¹⁵³Sm has a half-life of 46.3 hours, undergoing β− decay into ¹⁵³Eu.

final_sentence: ¹⁵³Sm has a half-life of 46.3 hours, undergoing β− decay into ¹⁵³Eu.