Sulfur-32

Properties and data of the isotope ³²S.

Contents

Sulfur-32 is a naturally occurring, stable isotope of the chemical element sulfur, which has 16 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 32.

A report on the discovery was published in 1920; according to this report, sulfur-32 was identified by measuring the mass spectrum [1].

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

General data

Name of the isotope:Sulfur-32; S-32Symbol:³²S or 3216SMass number A:32 (= number of nucleons)Atomic number Z:16 (= number of protons)Neutrons N:16Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1 (= neutron-proton ratio)Neutron excess (N-Z):0Isotopic mass:31.9720711735(14) u (atomic weight of Sulfur-32)Nuclide mass:31.963294 u (calculated nuclear mass without electrons)Mass excess:-26.01553 MeVMass defect:0.2917679945 u (per nucleus)Nuclear binding energy:271.78013627 MeV (per nucleus)
8.49312926 MeV (average binding energy per nucleon)Separation energy:S_N = 15.04432(23) MeV (first neutron)
S_P = 8.8639638(15) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:3.2611(18) femtometer fmYear of discovery:1920

Parent Nuclides

Direct parent isotopes are: ³³Ar, ³²Cl, ³²P, ³⁶K.

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+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 16) and isobaric (same nucleon number A = 32) with Sulfur-32. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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