Calcium-43
Properties and data of the isotope 43Ca.
Calcium-43 is a stable, naturally occurring isotope of the chemical element calcium, which has 23 neutrons in its atomic nucleus in addition to the element-specific 20 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 43.
Ca-43 was first described and characterized using mass spectrometric and photometric analyses in 1934 [1].
See also: List of individual Calcium isotopes (and general data sources).
General data
Name of the isotope:Calcium-43; Ca-43Symbol:43Ca or 4320CaMass number A:43 (= number of nucleons)Atomic number Z:20 (= number of protons)Neutrons N:23Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.15 (= neutron-proton ratio)Neutron excess (N-Z):3Isotopic mass:42.95876638(24) u (atomic weight of Calcium-43)Nuclide mass:42.947795 u (calculated nuclear mass without electrons)Mass excess:-38.40887 MeVMass defect:0.397027328 u (per nucleus)Nuclear binding energy:369.82857387 MeV (per nucleus)
8.60066451 MeV (average binding energy per nucleon)Separation energy:SN = 7.93290(17) MeV (first neutron)
SP = 10.67581(25) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)7/2-Magnetic dipole moment:μ(μN) = -1.31733(6)Charge radius:3.4954(19) femtometer fmMirror nucleus:Vanadium-43Year of discovery:1934
Parent Nuclides
Direct parent isotopes are: 43K, 43Sc.
Occurrence
Comparison of the natural Calcium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
| | Atomic Mass ma | Quantity | Half-life | Spin |
|---|
Calcium
Isotopic mixture | 40.078 u | 100 % | | |
| Isotope 40Ca | 39.9625909(2) u | 96.941(156) % | stable | 0+ |
| Isotope 41Ca | 40.96227792(15) u |
[trace] | 9.94(15) × 104 a | 7/2- |
| Isotope 42Ca | 41.958618(1) u | 0.647(23) % | stable | 0+ |
| Isotope 44Ca | 43.955482(2) u | 2.086(110) % | stable | 0+ |
| Isotope 46Ca | 45.95369(2) u | 0.004(3) % | stable | 0+ |
| Isotope 48Ca | 47.952522654(19) u | 0.187(21) % | 5.3 × 1019 a | 0+ |
| Isotope 43Ca | 42.95876638(24) u | 0.135(10) % | stable | 7/2- |
NMR data
Nuclear magnetic properties and parameters of the NMR active Nuclide 43Ca
Isotope:43Ca-NMRQuantity:0.135(10) %Spin:7/2-Nuclearmagnetic moment
μ/μN:-1.31733(6)Gyromagnetic ratio γ:0 · 107 rad T-1 s-1
0.00000 MHz T-1Nuclear g-factor:gl = -0.37638Quadrupole moment Q:- 0.0408(8) barn (100 fm2)Resonance frequency:v0 = 2.8697 MHz at 1 TRelative Sensitivity:[related to 1H = 1.000]:
0.00643 (H0 = const.)
1.4154 (v0 = const.)
0.00000868 (at natural abundance)
relative receptivity as compared to 13C:
0.0510 (at natural abundance)Reference compound:
(conditions)0.1 M calcium dichloride solution CaClâ‚‚ in deuterium oxide D2OFrequency ratio:Ξ(43Ca) = 6.730029 % [based on the reference substance]
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 23) and isobaric (same nucleon number A = 43) with Calcium-43. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 23 | Isobar A = 43 |
|---|
| 10 | 33Ne | |
| 11 | 34Na | |
| 12 | 35Mg | |
| 13 | 36Al | 43Al |
| 14 | 37Si | 43Si |
| 15 | 38P | 43P |
| 16 | 39S | 43S |
| 17 | 40Cl | 43Cl |
| 18 | 41Ar | 43Ar |
| 19 | 42K | 43K |
| 20 | 43Ca | 43Ca |
| 21 | 44Sc | 43Sc |
| 22 | 45Ti | 43Ti |
| 23 | 46V | 43V |
| 24 | 47Cr | 43Cr |
| 25 | 48Mn | 43Mn |
| 26 | 49Fe | |
| 27 | 50Co | |
| 28 | 51Ni | |
External data and identifiers
Literature and References
[1] - F. W. Aston:
Calcium Isotopes and the Problem of Potassium.
In: Nature, 133, 869, (1934), DOI 10.1038/133869b0.
[2] - Sean T. Holmes et al.:
Calculations of solid-state 43 Ca NMR parameters: A comparison of periodic and cluster approaches and an evaluation of DFT functionals.
In: Journal of Computational Chemistry, 38, 13, (2017), DOI 10.1002/jcc.24763.
Last update: 2026-01-11
Perma link: https://www.chemlin.org/isotope/calcium-43
© 1996 - 2026 ChemLin
