Arsenic-91

Properties and data of the isotope ⁹¹As.

Content

General data

Name of the isotope:Arsenic-91; As-91Symbol:⁹¹As or 9133AsMass number A:91 (= number of nucleons)Atomic number Z:33 (= number of protons)Neutrons N:58Isotopic mass:90.96039(43) u (atomic weight of Arsenic-91)Nuclide mass:90.9422875 u (calculated nuclear mass without electrons)Mass excess:-36.89648 MeVMass defect:0.80040118399999 u (per nucleus)Nuclear binding energy:745.56890049 MeV (per nucleus)
8.19306484 MeV (average binding energy per nucleon)Separation energy:S_N = 3.64(56) MeV (first neutron)
S_P = 14.96(64) MeV (first proton)Half-life:Spin and parity:
(nuclear angular momentum)Year of discovery:1997

Radioactive Decay

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁹¹Se		16.68(59) MeV
β^-, n	⁹⁰Se		10.83(52) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 58) and isobaric (same nucleon number A = 91) with Arsenic-91. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 58	Isobar A = 91
32	⁹⁰Ge
33	⁹¹As	⁹¹As
34	⁹²Se	⁹¹Se
35	⁹³Br	⁹¹Br
36	⁹⁴Kr	⁹¹Kr
37	⁹⁵Rb	⁹¹Rb
38	⁹⁶Sr	⁹¹Sr
39	⁹⁷Y	⁹¹Y
40	⁹⁸Zr	⁹¹Zr
41	⁹⁹Nb	⁹¹Nb
42	¹⁰⁰Mo	⁹¹Mo
43	¹⁰¹Tc	⁹¹Tc
44	¹⁰²Ru	⁹¹Ru
45	¹⁰³Rh	⁹¹Rh
46	¹⁰⁴Pd	⁹¹Pd
47	¹⁰⁵Ag
48	¹⁰⁶Cd
49	¹⁰⁷In
50	¹⁰⁸Sn
51	¹⁰⁹Sb
52	¹¹⁰Te
53	¹¹¹I
54	¹¹²Xe
55	¹¹³Cs
56	¹¹⁴Ba