Calcium-42

Properties and data of the isotope ⁴²Ca.

Contents

General data

Name of the isotope:Calcium-42; Ca-42Symbol:⁴²Ca or 4220CaMass number A:42 (= number of nucleons)Atomic number Z:20 (= number of protons)Neutrons N:22Isotopic mass:41.958618(1) u (atomic weight of Calcium-42)Nuclide mass:41.9476466 u (calculated nuclear mass without electrons)Mass excess:-38.54708 MeVMass defect:0.388510792 u (per nucleus)Nuclear binding energy:361.89547168 MeV (per nucleus)
8.61655885 MeV (average binding energy per nucleon)Separation energy:S_N = 11.48067(6) MeV (first neutron)
S_P = 10.27667(15) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:3.5081(21) femtometer fmMirror nucleus:Titanium-42Year of discovery:1934

Parent Nuclides

Direct parent isotopes are: ⁴²K, ⁴²Sc.

Occurrence

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

	Atomic Mass m_a	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 ⁴³Ca	42.958766(2) u	0.135(10) %	stable	7/2-
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+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 22) and isobaric (same nucleon number A = 42) with Calcium-42. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 22	Isobar A = 42
9	³¹F
10	³²Ne
11	³³Na
12	³⁴Mg
13	³⁵Al	⁴²Al
14	³⁶Si	⁴²Si
15	³⁷P	⁴²P
16	³⁸S	⁴²S
17	³⁹Cl	⁴²Cl
18	⁴⁰Ar	⁴²Ar
19	⁴¹K	⁴²K
20	⁴²Ca	⁴²Ca
21	⁴³Sc	⁴²Sc
22	⁴⁴Ti	⁴²Ti
23	⁴⁵V	⁴²V
24	⁴⁶Cr	⁴²Cr
25	⁴⁷Mn	⁴²Mn
26	⁴⁸Fe
27	⁴⁹Co
28	⁵⁰Ni