Phosphorus-31

Properties and data of the isotope ³¹P.

Content

General data

Name of the isotope:Phosphorus-31; P-31Symbol:³¹P or 3115PMass number A:31 (= number of nucleons)Atomic number Z:15 (= number of protons)Neutrons N:16Isotopic mass:30.973761998(5) u (atomic weight of Phosphorus-31)Nuclide mass:30.9655334 u (calculated nuclear mass without electrons)Mass excess:-24.44054 MeVMass defect:0.282252138 u (per nucleus)Nuclear binding energy:262.91617303 MeV (per nucleus)
8.48116687 MeV (average binding energy per nucleon)Separation energy:S_N = 12.31100(7) MeV (first neutron)
S_P = 7.29655(2) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)1/2+Magnetic dipole moment:μ(μ_N) = + 1.130925(5)Charge radius:3.1889(19) femtometer fmMirror nucleus:Sulfur-31Year of discovery:1920

Parent Nuclides

Direct parent isotopes are: ³¹S, ³¹Si, ³²Cl.

Occurrence

Comparison of the natural Phosphorus isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Phosphorus Isotopic mixture	30.973761998 u	100 %
Isotope ³¹P	30.973761998(5) u	100 %	stable	1/2+

NMR data

Nuclear magnetic properties of the NMR active Nuclide ³¹P

Isotope:³¹P-NMRQuantity:100 %Spin:1/2+Nuclearmagnetic moment
μ/μ_N:+ 1.130925(5)Gyromagnetic ratio γ:10.841 · 10⁷ rad T^-1 s^-1Nuclear g-factor:g_l = 2.26185Resonance frequency:v₀ = 17.2515 at 1 TRelative Sensitivity:0.06652 (H₀ = const.)
0.4052 (v₀ = const.)
[related to ¹H = 1.000]

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 16) and isobaric (same nucleon number A = 31) with Phosphorus-31. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 16	Isobar A = 31
5	²¹B
6	²²C
7	²³N
8	²⁴O
9	²⁵F	³¹F
10	²⁶Ne	³¹Ne
11	²⁷Na	³¹Na
12	²⁸Mg	³¹Mg
13	²⁹Al	³¹Al
14	³⁰Si	³¹Si
15	³¹P	³¹P
16	³²S	³¹S
17	³³Cl	³¹Cl
18	³⁴Ar	³¹Ar
19	³⁵K
20	³⁶Ca
21	³⁷Sc
22	³⁸Ti