Cs

Caesium-129m

Protons (Z)

55

Neutrons (N)

74

Mass number

129

Half-Life

718.0 ns

Abundance

---

Mass

128.907 u

Mass Excess

-86,924.0 keV

Spin

(11/2-)

Discovered

1977

Binding energy per nucleon

8,412 keV

Neutron separation energy

9,063 keV

Proton separation energy

4,352 keV

Decay Mode

γCaesium-129100%

Decay chain

Caesium-129Z 55 · N 74718.0 ns
γ100%
β⁺100%