Phosphorus-25

Properties and data of the isotope ²⁵P.

Content

General data

Name of the isotope:Phosphorus-25; P-25Symbol:²⁵P or 2515PMass number A:25 (= number of nucleons)Atomic number Z:15 (= number of protons)Neutrons N:10Isotopic mass:25.02119(43) u (atomic weight of Phosphorus-25)Nuclide mass:25.0129614 u (calculated nuclear mass without electrons)Mass excess:19.73836 MeVMass defect:0.18283464 u (per nucleus)Nuclear binding energy:170.30937015 MeV (per nucleus)
6.81237481 MeV (average binding energy per nucleon)Separation energy:S_N = 21.65(64) MeV (first neutron)Half-life:30 nsDecay constant λ:23104906.018665 s^-1Specific activity α:5.56563994 × 10⁺²⁹ Bq g^-1
1.504227011891 × 10⁺¹⁹ Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2+)Mirror nucleus:Neon-25

Radioactive Decay

Half-life T_½ = 30 ns respectively 3.0 × 10^-8 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
p	²⁴Si	100 %	15.910 MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 10) and isobaric (same nucleon number A = 25) with Phosphorus-25. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 10	Isobar A = 25
3	¹³Li
4	¹⁴Be
5	¹⁵B
6	¹⁶C
7	¹⁷N	²⁵N
8	¹⁸O	²⁵O
9	¹⁹F	²⁵F
10	²⁰Ne	²⁵Ne
11	²¹Na	²⁵Na
12	²²Mg	²⁵Mg
13	²³Al	²⁵Al
14	²⁴Si	²⁵Si
15	²⁵P	²⁵P
16	²⁶S