See also: List of individual Calcium isotopes (and general data sources).
General data
Name of the isotope:Calcium-44; Ca-44Symbol:44Ca or 4420CaMass number A:44 (= number of nucleons)Atomic number Z:20 (= number of protons)Neutrons N:24Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.2 (= neutron-proton ratio)Neutron excess (N-Z):4Isotopic mass:43.955482(2) u (atomic weight of Calcium-44)Nuclide mass:43.9445106 u (calculated nuclear mass without electrons)Mass excess:-41.46825 MeVMass defect:0.408976624 u (per nucleus)Nuclear binding energy:380.9592714 MeV (per nucleus) 8.65816526 MeV (average binding energy per nucleon)Separation energy:SN = 11.13117(23) MeV (first neutron) SP = 12.1823(5) MeV (first proton)Half-life:stableSpin and parity: (nuclear angular momentum)0+Charge radius:3.5179(21) femtometer fmMirror nucleus:Chromium-44Year of discovery:1922
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 years
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 years
0+
Isotope 43Ca
42.95876638(24) u
0.135(10) %
stable
7/2-
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 24) and isobaric (same nucleon number A = 44) with Calcium-44. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
