Arsenic-66

Properties and data of the isotope ⁶⁶As.

Content

General data

Name of the isotope:Arsenic-66; As-66Symbol:⁶⁶As or 6633AsMass number A:66 (= number of nucleons)Atomic number Z:33 (= number of protons)Neutrons N:33Isotopic mass:65.944149(6) u (atomic weight of Arsenic-66)Nuclide mass:65.9260465 u (calculated nuclear mass without electrons)Mass excess:-52.02487 MeVMass defect:0.600019284 u (per nucleus)Nuclear binding energy:558.91436293 MeV (per nucleus)
8.46839944 MeV (average binding energy per nucleon)Separation energy:S_N = 13.16(8) MeV (first neutron)
S_P = 2.836(6) MeV (first proton)Half-life:95.77(23) msDecay constant λ:7.2376232699169 s^-1Specific activity α:6.705536434245 × 10⁺²² Bq g^-1
1812307144390.7 Ci g^-1Spin and parity:
(nuclear angular momentum)(0+)Year of discovery:1978

Radioactive Decay

Half-life T_½ = 95.77(23) ms respectively 9.577 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	⁶⁶Ge	100 %	9.582(6) MeV

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
^66m1As	1356.63(17) keV	1.1(1) μs	(5+)
^66m2As	3023.8(3) keV	8.2	(9+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 33) and isobaric (same nucleon number A = 66) with Arsenic-66. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 33	Isobar A = 66
16	⁴⁹S
17	⁵⁰Cl
18	⁵¹Ar
19	⁵²K
20	⁵³Ca
21	⁵⁴Sc
22	⁵⁵Ti
23	⁵⁶V	⁶⁶V
24	⁵⁷Cr	⁶⁶Cr
25	⁵⁸Mn	⁶⁶Mn
26	⁵⁹Fe	⁶⁶Fe
27	⁶⁰Co	⁶⁶Co
28	⁶¹Ni	⁶⁶Ni
29	⁶²Cu	⁶⁶Cu
30	⁶³Zn	⁶⁶Zn
31	⁶⁴Ga	⁶⁶Ga
32	⁶⁵Ge	⁶⁶Ge
33	⁶⁶As	⁶⁶As
34	⁶⁷Se	⁶⁶Se
35	⁶⁸Br	⁶⁶Br
36	⁶⁹Kr