Phosphorus-35

Properties and data of the isotope ³⁵P.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Phosphorus-35 is a radioisotope of the chemical element phosphorus, which has 20 neutrons in its atomic nucleus in addition to the element-specific 15 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 35. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ³⁵P is exclusively for academic purposes.

The radioactive isotope was first described in 1971; according to this, phosphorus-35 was formed as a fission product when a thorium-232 template was irradiated with argon-40 ions of an energy of 290 MeV [1].

See also: List of individual Phosphorus isotopes (and general data sources).

General data

Name of the isotope:Phosphorus-35; P-35Symbol:³⁵P or 3515PMass number A:35 (= number of nucleons)Atomic number Z:15 (= number of protons)Neutrons N:20Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.3333333333333 (= neutron-proton ratio)Neutron excess (N-Z):5Isotopic mass:34.9733140(20) u (atomic weight of Phosphorus-35)Nuclide mass:34.9650854 u (calculated nuclear mass without electrons)Mass excess:-24.85785 MeVMass defect:0.3173598 u (per nucleus)Nuclear binding energy:295.61874954 MeV (per nucleus)
8.44624999 MeV (average binding energy per nucleon)Separation energy:S_N = 8.3804(20) MeV (first neutron)
S_P = 12.1551(20) MeV (first proton)Half-life:47.3(8) sDecay constant λ:0.014654274430443 s^-1Specific activity α:2.59559131824 × 10⁺²⁰ Bq g^-1
7015111670.9297 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2+Mirror nucleus:Calcium-35Year of discovery:1971

Radioactive Decay

Half-life T_½ = 47.3(8) s respectively 4.73 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	³⁵S	100 %	3.9884(19) MeV

Parent Nuclides

Direct parent isotopes are: ³⁵Si, ³⁶Si.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 20) and isobaric (same nucleon number A = 35) with Phosphorus-35. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 20	Isobar A = 35
8	²⁸O
9	²⁹F
10	³⁰Ne
11	³¹Na	³⁵Na
12	³²Mg	³⁵Mg
13	³³Al	³⁵Al
14	³⁴Si	³⁵Si
15	³⁵P	³⁵P
16	³⁶S	³⁵S
17	³⁷Cl	³⁵Cl
18	³⁸Ar	³⁵Ar
19	³⁹K	³⁵K
20	⁴⁰Ca	³⁵Ca
21	⁴¹Sc
22	⁴²Ti
23	⁴³V
24	⁴⁴Cr
25	⁴⁵Mn
26	⁴⁶Fe
27	⁴⁷Co
28	⁴⁸Ni