Arsenic-75

Properties and data of the isotope ⁷⁵As.

Contents

General Data

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

Arsenic-75 is the only stable isotope of the chemical element arsenic. The atomic nucleus of the nuclide consists of 33 element-specific protons and 42 neutrons; the sum of these nuclear building blocks results in a mass number of 75. As an independent isotope, ⁷⁵As was identified and characterized by mass spectrography in 1920 [1].

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

General data

Name of the isotope:Arsenic-75; As-75Symbol:⁷⁵As or 7533AsMass number A:75 (= number of nucleons)Atomic number Z:33 (= number of protons)Neutrons N:42Isotopic mass:74.921595(6) u (atomic weight of Arsenic-75)Nuclide mass:74.9034925 u (calculated nuclear mass without electrons)Mass excess:-73.03379 MeVMass defect:0.700557528 u (per nucleus)Nuclear binding energy:652.56513399 MeV (per nucleus)
8.70086845 MeV (average binding energy per nucleon)Separation energy:S_N = 10.2455(19) MeV (first neutron)
S_P = 6.9007(9) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)3/2-Magnetic dipole moment:μ(μ_N) = +1.4383(3)Charge radius:4.0968(20) femtometer fmYear of discovery:1920

Parent Nuclides

Direct parent isotopes are: ⁷⁵Se, ⁷⁵Ge.

Occurrence

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

	Atomic Mass m_a	Quantity	Half-life	Spin
Arsenic Isotopic mixture	74.921595 u	100 %
Isotope ⁷⁵As	74.921595(6) u	100 %	stable	3/2-

NMR data

Nuclear magnetic properties of the NMR active Nuclide ⁷⁵As

Isotope:⁷⁵As-NMRQuantity:100 %Spin:3/2-Nuclearmagnetic moment
μ/μ_N:+1.4383(3)Gyromagnetic ratio γ:4.5961 · 10⁷ rad T^-1 s^-1Nuclear g-factor:g_l = 0.95886666666667Quadrupole moment Q:+ 0.311(2) barn (100 fm²)Resonance frequency:v₀ = 7.3150 at 1 TFrequency ratio:Ξ(⁷⁵As) = 17.122614 %Relative Sensitivity:0.02536 (H₀ = const.)
0.8590 (v₀ = const.)
[related to ¹H = 1.000]Reference compound:
(conditions)Solution of 0.5 M sodium hexafluoroarsenate in acetonitrile-d3.

The only stable nuclide of arsenic is quadrupolar and thus NMR active. However, ⁷⁵As NMR spectroscopy is only suitable for the investigation of smaller arsenic ions: the quadrupolar nucleus shows medium sensitivity and broad lines. The chemical shift range is wide and also different for different types of As compounds - but 75As NMR spectroscopy can be useful for distinguishing and quantifying the different species.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^75mAs	303.9243(8) keV	17.62(23) ms	9/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 42) and isobaric (same nucleon number A = 75) with Arsenic-75. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 42	Isobar A = 75
21	⁶³Sc
22	⁶⁴Ti
23	⁶⁵V
24	⁶⁶Cr
25	⁶⁷Mn
26	⁶⁸Fe
27	⁶⁹Co	⁷⁵Co
28	⁷⁰Ni	⁷⁵Ni
29	⁷¹Cu	⁷⁵Cu
30	⁷²Zn	⁷⁵Zn
31	⁷³Ga	⁷⁵Ga
32	⁷⁴Ge	⁷⁵Ge
33	⁷⁵As	⁷⁵As
34	⁷⁶Se	⁷⁵Se
35	⁷⁷Br	⁷⁵Br
36	⁷⁸Kr	⁷⁵Kr
37	⁷⁹Rb	⁷⁵Rb
38	⁸⁰Sr	⁷⁵Sr
39	⁸¹Y
40	⁸²Zr
41	⁸³Nb
42	⁸⁴Mo
43	⁸⁵Tc
44	⁸⁶Ru

External data and identifiers

Adopted Levels, Gammas:NuDat 75As

Literature and References

[1] - F. W. Aston:
The mass-spectra of chemical elements.
In: Philosophical Magazine and Journal of Science, 40, 239, 632, (1920), DOI 10.1080/14786441108636168.

[2] - Erica Brendler et al.:
⁷⁵As Nuclear Magnetic Resonance Spectroscopic Investigation of the Thioarsenate Speciation in Strongly Alkaline Sulfidic Leaching Solutions.
In: Molecules, 29(12), 2848, (2024), DOI 10.3390/molecules29122848.