Calcium-45 is a radioisotope of the chemical element calcium, which has 25 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 45.
The radioactive nuclide was discovered during the irradiation of natural Ca samples (containing approximately 2% calcium-44) with 8 MeV deuterons (hydrogen-2 nuclei) [1]:
44Ca(d,n)45Ca.,
44Ca(n,γ)45Ca.
See also: List of individual Calcium isotopes (and general data sources).
General data
Name of the isotope:Calcium-45; Ca-45Symbol:45Ca or 4520CaMass number A:45 (= number of nucleons)Atomic number Z:20 (= number of protons)Neutrons N:25Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.25 (= neutron-proton ratio)Neutron excess (N-Z):5Isotopic mass:44.9561863(4) u (atomic weight of Calcium-45)Nuclide mass:44.9452149 u (calculated nuclear mass without electrons)Mass excess:-40.8122 MeVMass defect:0.41693724 u (per nucleus)Nuclear binding energy:388.37453744 MeV (per nucleus) 8.63054528 MeV (average binding energy per nucleon)Separation energy:SN = 7.41482(17) MeV (first neutron) SP = 12.3197(6) MeV (first proton)Half-life:162.61(9) dDecay constant λ:4.933606058690 × 10-8 s-1Specific activity α:6.608850212862 × 10+14 Bq g-1 17861.75733206 Ci g-1Spin and parity: (nuclear angular momentum)7/2-Magnetic dipole moment:μ(μN) = - 1.3264(13)Quadrupole moment Q:+ 0.038(12) barn (100 fm2)Nuclear g-factor:gl = -0.37897142857143Charge radius:3.4944(21) femtometer fmMirror nucleus:Manganese-45Year of discovery:1940
Radioactive Decay
Half-life T½ = 162.61(9) d respectively 1.4049504 × 107 seconds s.
The following table shows the atomic nuclei that are isotonic (same neutron number N = 25) and isobaric (same nucleon number A = 45) with Calcium-45. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
