Einsteinium-251 (Es-251)

Identity

Protons

99

Neutrons

152

Mass number

251

Mass

251.1 ± 5.7 u

Mass excess

74.512 MeV

Spin

3/2-

Stability

Half-life: 1.38 days

Natural occurrence

Not found in nature

Decays to

• electron capture 99.5 % → Cf-251
• alpha 0.50 % → Bk-247