Arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, ...

(₃₃As) has 33 known

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

s and at least 10

isomers In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. ...

. Only one of these isotopes, ⁷⁵As, is stable; as such, it is considered a

monoisotopic element A monoisotopic element is an element which has only a single stable isotope (nuclide). There are only 26 elements that have this property. A list is given in a following section. Stability is experimentally defined for chemical elements, as ther ...

. The longest-lived

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

is ⁷³As with a half-life of 80 days. Arsenic has been proposed as a " salting" material for

nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...

s (

cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...

is another, better-known salting material). A jacket of ⁷⁵As, irradiated by the intense high-energy neutron flux from an exploding

thermonuclear weapon A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a low ...

, would transmute into the radioactive isotope ⁷⁶As with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

of 1.0778 days and produce approximately 1.13

MeV In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacu ...

gamma radiation, significantly increasing the radioactivity of the weapon's

fallout Nuclear fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and the shock wave has passed. It commonly refers to the radioac ...

for several hours. Such a weapon is not known to have ever been built, tested, or used.

List of isotopes

, - , ⁶⁰As , style="text-align:right" , 33 , style="text-align:right" , 27 , 59.99313(64)# , , p , ⁵⁹Ge , 5+# , , , - , ⁶¹As , style="text-align:right" , 33 , style="text-align:right" , 28 , 60.98062(64)# , , p , ⁶⁰Ge , 3/2−# , , , - , ⁶²As , style="text-align:right" , 33 , style="text-align:right" , 29 , 61.97320(32)# , , p , ⁶¹Ge , 1+# , , , - , ⁶³As , style="text-align:right" , 33 , style="text-align:right" , 30 , 62.96369(54)# , , p , ⁶²Ge , (3/2−)# , , , - , ⁶⁴As , style="text-align:right" , 33 , style="text-align:right" , 31 , 63.95757(38)# , 40(30) ms
8(+43-7) ms, β⁺ , ⁶⁴Ge , 0+# , , , - , ⁶⁵As , style="text-align:right" , 33 , style="text-align:right" , 32 , 64.94956(32)# , 170(30) ms , β⁺ , ⁶⁵Ge , 3/2−# , , , - , ⁶⁶As , style="text-align:right" , 33 , style="text-align:right" , 33 , 65.94471(73) , 95.77(23) ms , β⁺ , ⁶⁶Ge , (0+) , , , - , style="text-indent:1em" , ^66m1As , colspan="3" style="text-indent:2em" , 1356.70(17) keV , 1.1(1) µs , , , (5+) , , , - , style="text-indent:1em" , ^66m2As , colspan="3" style="text-indent:2em" , 3023.9(3) keV , 8.2(5) µs , , , (9+) , , , - , ⁶⁷As , style="text-align:right" , 33 , style="text-align:right" , 34 , 66.93919(11) , 42.5(12) s , β⁺ , ⁶⁷Ge , (5/2−) , , , - , ⁶⁸As , style="text-align:right" , 33 , style="text-align:right" , 35 , 67.93677(5) , 151.6(8) s , β⁺ , ⁶⁸Ge , 3+ , , , - , style="text-indent:1em" , ^68mAs , colspan="3" style="text-indent:2em" , 425.21(16) keV , 111(20) ns
107(+23-16) ns, , , 1+ , , , - , ⁶⁹As , style="text-align:right" , 33 , style="text-align:right" , 36 , 68.93227(3) , 15.2(2) min , β⁺ , ⁶⁹Ge , 5/2− , , , - , ⁷⁰As , style="text-align:right" , 33 , style="text-align:right" , 37 , 69.93092(5) , 52.6(3) min , β⁺ , ⁷⁰Ge , 4(+#) , , , - , style="text-indent:1em" , ^70mAs , colspan="3" style="text-indent:2em" , 32.008(23) keV , 96(3) µs , , , 2(+) , , , - , ⁷¹As , style="text-align:right" , 33 , style="text-align:right" , 38 , 70.927112(5) , 65.28(15) h , β⁺ , ⁷¹Ge , 5/2− , , , - , ⁷²As , style="text-align:right" , 33 , style="text-align:right" , 39 , 71.926752(5) , 26.0(1) h , β⁺ , ⁷²Ge , 2− , , , - , ⁷³As , style="text-align:right" , 33 , style="text-align:right" , 40 , 72.923825(4) , 80.30(6) d , EC , ⁷³Ge , 3/2− , , , - , rowspan=2, ⁷⁴As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 41 , rowspan=2, 73.9239287(25) , rowspan=2, 17.77(2) d , β⁺ (66%) , ⁷⁴Ge , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , β⁻ (34%) , ⁷⁴Se , - , ⁷⁵As , style="text-align:right" , 33 , style="text-align:right" , 42 , 74.9215965(20) , colspan=3 align=center, Stable , 3/2− , 1.0000 , , - , style="text-indent:1em" , ^75mAs , colspan="3" style="text-indent:2em" , 303.9241(7) keV , 17.62(23) ms , , , 9/2+ , , , - , rowspan=2, ⁷⁶As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 43 , rowspan=2, 75.922394(2) , rowspan=2, 1.0942(7) d , β⁻ (99.98%) , ⁷⁶Se , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , EC (.02%) , ''⁷⁶Ge'' , - , style="text-indent:1em" , ^76mAs , colspan="3" style="text-indent:2em" , 44.425(1) keV , 1.84(6) µs , , , (1)+ , , , - , ⁷⁷As , style="text-align:right" , 33 , style="text-align:right" , 44 , 76.9206473(25) , 38.83(5) h , β⁻ , ^77mSe , 3/2− , , , - , style="text-indent:1em" , ^77mAs , colspan="3" style="text-indent:2em" , 475.443(16) keV , 114.0(25) µs , , , 9/2+ , , , - , ⁷⁸As , style="text-align:right" , 33 , style="text-align:right" , 45 , 77.921827(11) , 90.7(2) min , β⁻ , ⁷⁸Se , 2− , , , - , ⁷⁹As , style="text-align:right" , 33 , style="text-align:right" , 46 , 78.920948(6) , 9.01(15) min , β⁻ , ^79mSe , 3/2− , , , - , style="text-indent:1em" , ^79mAs , colspan="3" style="text-indent:2em" , 772.81(6) keV , 1.21(1) µs , , , (9/2)+ , , , - , ⁸⁰As , style="text-align:right" , 33 , style="text-align:right" , 47 , 79.922534(25) , 15.2(2) s , β⁻ , ⁸⁰Se , 1+ , , , - , ⁸¹As , style="text-align:right" , 33 , style="text-align:right" , 48 , 80.922132(6) , 33.3(8) s , β⁻ , ^81mSe , 3/2− , , , - , ⁸²As , style="text-align:right" , 33 , style="text-align:right" , 49 , 81.92450(21) , 19.1(5) s , β⁻ , ''⁸²Se'' , (1+) , , , - , style="text-indent:1em" , ^82mAs , colspan="3" style="text-indent:2em" , 250(200) keV , 13.6(4) s , β⁻ , ''⁸²Se'' , (5-) , , , - , ⁸³As , style="text-align:right" , 33 , style="text-align:right" , 50 , 82.92498(24) , 13.4(3) s , β⁻ , ^83mSe , 3/2−# , , , - , rowspan=2, ⁸⁴As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 51 , rowspan=2, 83.92906(32)# , rowspan=2, 4.02(3) s , β⁻ (99.721%) , ⁸⁴Se , rowspan=2, (3)(+#) , rowspan=2, , rowspan=2, , - , β⁻, n (.279%) , ⁸³Se , - , style="text-indent:1em" , ^84mAs , colspan="3" style="text-indent:2em" , 0(100)# keV , 650(150) ms , , , , , , - , rowspan=2, ⁸⁵As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 52 , rowspan=2, 84.93202(21)# , rowspan=2, 2.021(10) s , β⁻, n (59.4%) , ⁸⁴Se , rowspan=2, (3/2−)# , rowspan=2, , rowspan=2, , - , β⁻ (40.6%) , ⁸⁵Se , - , rowspan=2, ⁸⁶As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 53 , rowspan=2, 85.93650(32)# , rowspan=2, 0.945(8) s , β⁻ (67%) , ⁸⁶Se , rowspan=2, , rowspan=2, , rowspan=2, , - , β⁻, n (33%) , ⁸⁵Se , - , rowspan=2, ⁸⁷As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 54 , rowspan=2, 86.93990(32)# , rowspan=2, 0.56(8) s , β⁻ (84.6%) , ⁸⁷Se , rowspan=2, 3/2−# , rowspan=2, , rowspan=2, , - , β⁻, n (15.4%) , ⁸⁶Se , - , rowspan=2, ⁸⁸As , rowspan=2 style="text-align:right" , 33 , rowspan=2 style="text-align:right" , 55 , rowspan=2, 87.94494(54)# , rowspan=2, 300# ms
300 ns, β⁻ , ⁸⁸Se , rowspan=2, , rowspan=2, , rowspan=2, , - , β⁻, n , ⁸⁷Se , - , ⁸⁹As , style="text-align:right" , 33 , style="text-align:right" , 56 , 88.94939(54)# , 200# ms
300 ns, β⁻ , ⁸⁹Se , 3/2−# , , , - , ⁹⁰As , style="text-align:right" , 33 , style="text-align:right" , 57 , 89.95550(86)# , 80# ms
300 ns, , , , , , - , ⁹¹As , style="text-align:right" , 33 , style="text-align:right" , 58 , 90.96043(97)# , 50# ms
300 ns, , , 3/2−# , , , - , ⁹²As , style="text-align:right" , 33 , style="text-align:right" , 59 , 91.96680(97)# , 30# ms
300 ns, , , , ,

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** * A.Shore, A. Fritsch, M. Heim, A. Schuh, M. Thoennessen. ''Discovery of the Arsenic Isotopes.'
arXiv:0902.4361

External links

{{Authority control Arsenic