Nitrogen-15

Properties and data of the isotope ¹⁵N.

Contents

General Data

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

The stable isotope nitrogen-14, at 0.3795%, represents the much smaller part of the natural terrestrial element nitrogen (for composition see below). The atomic nucleus of the nuclide consists of 8 neutrons and the element-specific 7 protons.

According to a report from 1929, ¹⁵N was first identified and thus discovered on the basis of the absorption spectrum recorded with an E1-Hilger spectrograph of a gaseous NO sample illuminated with the continuous light of a hydrogen lamp [1].

General data

Name of the isotope:Nitrogen-15; N-15Symbol:¹⁵N or 157NMass number A:15 (= number of nucleons)Atomic number Z:7 (= number of protons)Neutrons N:8Isotopic mass:15.0001088983(6) u (atomic weight of Nitrogen-15)Nuclide mass:14.9962689 u (calculated nuclear mass without electrons)Mass excess:0.10144 MeVMass defect:0.1239856537 u (per nucleus)Nuclear binding energy:115.49189251 MeV (per nucleus)
7.6994595 MeV (average binding energy per nucleon)Separation energy:S_N = 10.8332956(8) MeV (first neutron)
S_P = 10.207425(4) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)1/2-Isobaric spin: 1/2Magnetic dipole moment:μ(μ_N) = -0.28318884(5)Charge radius:2.6058(80) femtometer fmMirror nucleus:Oxygen-15Year of discovery:1929

Parent Nuclides

Direct parent isotopes are: ¹⁵O, ¹⁵C.

Occurrence

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

	Atomic Mass m_a	Quantity	Half-life	Spin
Nitrogen Isotopic mixture	14.007 u	100 %
Isotope ¹⁴N	14.003074004251(241) u	99.6205 % [99.578 - 99.663 %]	stable	1+
Isotope ¹⁵N	15.0001088983(6) u	0.3795 % [0.337 - 0.422 %]	stable	1/2-

NMR data

Nuclear magnetic properties of the NMR active Nuclide ¹⁵N

Isotope:¹⁵N-NMRQuantity:0.3795 % [0.337 - 0.422 %]Spin:1/2-Nuclearmagnetic moment
μ/μ_N:-0.28318884(5)Gyromagnetic ratio γ:–2.71261804 · 10⁷ rad T^-1 s^-1Nuclear g-factor:g_l = -0.56637768Resonance frequency:v₀ = 4.3173 at 1 TFrequency ratio:Ξ(¹⁵N) = 10.136767 %Relative Sensitivity:0.00104 (H₀ = const.)
0.1014 (v₀ = const.)
[related to ¹H = 1.000]Reference compound:
(conditions)The recommended reference substance (IUPAC) is a solution of nitromethane (< 10 %) in purified chloroform-d. .

In practice, however, pressurized liquid ammonia (NH₃) is often used (δNH₃ = δCH₃NO₂ + 380.5 ppm).

Both natural N nuclides - Nitrogen-14 and -15 - are NMR active, although ¹⁵N has a nucleus that is not very sensitive to ¹⁵NMR spectroscopy and only accounts for 0.3795% of natural samples.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 8) and isobaric (same nucleon number A = 15) with Nitrogen-15. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 8	Isobar A = 15
2	¹⁰He
3	¹¹Li
4	¹²Be	¹⁵Be
5	¹³B	¹⁵B
6	¹⁴C	¹⁵C
7	¹⁵N	¹⁵N
8	¹⁶O	¹⁵O
9	¹⁷F	¹⁵F
10	¹⁸Ne	¹⁵Ne
11	¹⁹Na
12	²⁰Mg
13	²¹Al
14	²²Si