Sulfur-33

Properties and data of the isotope ³³S.

Contents

General Data

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

Sulfur-33 is a naturally occurring, stable isotope of the chemical element sulfur, which has 17 neutrons in its atomic nucleus in addition to the element-specific 16 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 33.

The first detection and thus the discovery of sulfur-33 was achieved in the 1920s with the Cavendish mass spectrograph [F. W. Aston, mass spectrographic identification of sulphur isotopes, reported in Nature (1926) and summarized in Isotopes, 2nd ed., 1927].

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

General data

Name of the isotope:Sulfur-33; S-33Symbol:³³S or 3316SMass number A:33 (= number of nucleons)Atomic number Z:16 (= number of protons)Neutrons N:17Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.0625 (= neutron-proton ratio)Neutron excess (N-Z):1Isotopic mass:32.9714589086(14) u (atomic weight of Sulfur-33)Nuclide mass:32.9626817 u (calculated nuclear mass without electrons)Mass excess:-26.58586 MeVMass defect:0.30104517540001 u (per nucleus)Nuclear binding energy:280.42177461 MeV (per nucleus)
8.49762953 MeV (average binding energy per nucleon)Separation energy:S_N = 8.6416392(19) MeV (first neutron)
S_P = 9.56995(4) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)3/2+Isobaric spin: 1/2Magnetic dipole moment:μ(μ_N) = +0.64325(2)Mirror nucleus:Chlorine-33Year of discovery:1926

Parent Nuclides

Direct parent isotopes are: ³³Cl, ³³P.

Occurrence

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

	Atomic Mass m_a	Quantity	Half-life	Spin
Sulfur Isotopic mixture	32.06 u	100 %
Isotope ³²S	31.9720711735(14) u	94.9 % [94.41 - 95.29 %]	stable	0+
Isotope ³⁴S	33.96786701(5) u	4.3 % [3.96 - 4.77 %]	stable	0+
Isotope ³⁵S	34.96903232(4) u	[trace]	87.37(4) d	3/2+
Isotope ³⁶S	35.96708069(20) u	0.01 % [0.0129 - 0.0187]	stable	0+
Isotope ³³S	32.9714589086(14) u	0.7 % [0.729 - 0.797 %]	stable	3/2+

NMR data

Nuclear magnetic properties and parameters of the NMR active Nuclide ³³S

Isotope:³³S-NMRQuantity:0.7 % [0.729 - 0.797 %]Spin:3/2+Nuclearmagnetic moment
μ/μ_N:+0.64325(2)Gyromagnetic ratio γ:2.055685 · 10⁷ rad T^-1 s^-1
3.27172 MHz T^-1Nuclear g-factor:g_l = 0.42883333333333Quadrupole moment Q:- 0.694(4) barn (100 fm²)Resonance frequency:v₀ = 3.2717 MHz at 1 TRelative Sensitivity:[related to ¹H = 1.000]:
0.00227 (H₀ = const.)
0.3842 (v₀ = const.)
0.0000172 (at natural abundance)
relative receptivity as compared to ¹³C:
0.101 (at natural abundance)
13.3 (enriched)Reference compound:
(conditions)Saturated solution of ammonium sulfate (NH₄)₂SO₄ in deuterium oxide D₂OFrequency ratio:Ξ(³³S) = 7.676000 % [based on the reference substance]Chemical shift range:ca. 964 ppm [-290 to 674]

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 17) and isobaric (same nucleon number A = 33) with Sulfur-33. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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

External data and identifiers

Adopted Levels, Gammas:NuDat 33S

Literature and References

[1] - Ioannis P. Gerothanassis, Leonid B. Kridvin:
³³S NMR: Recent Advances and Applications.
In: Molecules, 29(14), (2024), DOI 10.3390/molecules29143301.