Periodic Table/Samarium/¹²⁹Sm

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¹²⁹Sm

Samarium-129

Radioactive· Half-life: 550 ms

Nuclear Propertiesbinding energy · spin-parity · abundance

Protons (Z)

62

Neutrons (N)

67

Mass Number (A)

129

Atomic Mass

128.954557AMU

Spin / Parity

1/2+

Binding E/A

7.778keV

Natural Abundance

Trace / None

Half-life

550 ms

Decay Modesoverview · half-life · α · β⁻ · β⁺

β⁺

100.0%

β⁺p

Decay Chain

¹²⁹SmSamarium550 ms

β⁺100.0%

β⁺p¹²⁸Nd

¹²⁹PmPromethium2.40 s

β⁺100.0%

β⁺p¹²⁸Pr

p¹²⁸Nd

¹²⁹NdNeodymium6.80 s

β⁺100.0%

β⁺p¹²⁸Ce

¹²⁹PrPraseodymium30.0 s

β⁺100.0%

¹²⁹CeCerium3.50 min

β⁺100.0%

¹²⁹LaLanthanum11.6 min

β⁺100.0%

¹²⁹BaBarium2.23 h

β⁺100.0%

¹²⁹CsCesium1.34 d

β⁺100.0%

¹²⁹XeXenonSTABLE

9-step decay chain → stable · Primary path shown · branching ratios indicated

Other Isotopes of Samarium

128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168

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