Isotopes of ruthenium

Naturally occurring ruthenium (₄₄Ru) is composed of seven stable isotopes: 96, 98-102, 104 (of which the first and last may in the future be found radioactive). Additionally, 27 synthetic radioactive isotopes have been discovered. Of these radioisotopes, the most stable are ¹⁰⁶Ru with a half-life of 371.8 days or 1.018 years, ¹⁰³Ru, with a half-life of 39.245 days, and ⁹⁷Ru with a half-life of 2.837 days.

The other known isotopes run from ⁸⁷Ru to ¹²⁰Ru, and most of these have half-lives that are less than five minutes, except ⁹⁴Ru (51.8 minutes), ⁹⁵Ru (1.607 hours), and ¹⁰⁵Ru (4.44 hours).

The primary decay mode before the most abundant isotope, ¹⁰²Ru, is electron capture to isotopes of technetium, and after beta emission to isotopes of rhodium. Double beta decay is the allowed mode for the two observationally stable isotopes: ⁹⁶Ru and ¹⁰⁴Ru.

Because of the volatility of ruthenium tetroxide (), ruthenium isotopes with relatively short half-life are considered the next most hazardous airborne isotopes, after iodine-131, in case of release by a nuclear accident. The two most important isotopes of ruthenium so released are those with the longest half-life: ¹⁰³Ru ¹⁰⁶Ru.

List of isotopes

|-id=Ruthenium-85 | ⁸⁵Ru | style="text-align:right" | 44 | style="text-align:right" | 41 | 84.96712(54)# | 1#&nbsp;ms[>&nbsp;400&nbsp;ns] | | | 3/2−# | | |-id=Ruthenium-86 | ⁸⁶Ru | style="text-align:right" | 44 | style="text-align:right" | 42 | 85.95731(43)# | 50#&nbsp;ms[>&nbsp;400&nbsp;ns] | | | 0+ | | |-id=Ruthenium-87 | ⁸⁷Ru | style="text-align:right" | 44 | style="text-align:right" | 43 | 86.95091(43)# | 50#&nbsp;ms[>&nbsp;1.5&nbsp;μs] | | | 1/2−# | | |-id=Ruthenium-88 | rowspan=2|⁸⁸Ru | rowspan=2 style="text-align:right" | 44 | rowspan=2 style="text-align:right" | 44 | rowspan=2|87.941760(20) | rowspan=2|1.5(3)&nbsp;s | β⁺ (>96.4%) | ⁸⁸Tc | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p (<3.6%) | ⁸⁷Mo |-id=Ruthenium-89 | rowspan=2|⁸⁹Ru | rowspan=2 style="text-align:right" | 44 | rowspan=2 style="text-align:right" | 45 | rowspan=2|88.937338(26) | rowspan=2|1.32(3)&nbsp;s | β⁺ (96.7%) | ⁸⁹Tc | rowspan=2|(9/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (3.1%) | ⁸⁸Mo |-id=Ruthenium-90 | ⁹⁰Ru | style="text-align:right" | 44 | style="text-align:right" | 46 | 89.9303444(40) | 11.7(9)&nbsp;s | β⁺ | ⁹⁰Tc | 0+ | | |-id=Ruthenium-91 | ⁹¹Ru | style="text-align:right" | 44 | style="text-align:right" | 47 | 90.9267415(24) | 8.0(4)&nbsp;s | β⁺ | ⁹¹Tc | (9/2+) | | |-id=Ruthenium-91m | rowspan=2 style="text-indent:1em" | ^91mRu | rowspan=2 colspan="3" style="text-indent:2em" | 432(31)&nbsp;keV | rowspan=2|7.6(8)&nbsp;s | β⁺ (>99.9%) | ⁹¹Tc | rowspan=2|(1/2−) | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ⁹⁰Mo |-id=Ruthenium-92 | ⁹²Ru | style="text-align:right" | 44 | style="text-align:right" | 48 | 91.9202344(29) | 3.65(5)&nbsp;min | β⁺ | ⁹²Tc | 0+ | | |-id=Ruthenium-92m | style="text-indent:1em" | ^92mRu | colspan="3" style="text-indent:2em" | 2833.9(18)&nbsp;keV | 100(8)&nbsp;ns | IT | ⁹²Ru | (8+) | | |-id=Ruthenium-93 | ⁹³Ru | style="text-align:right" | 44 | style="text-align:right" | 49 | 92.9171044(22) | 59.7(6)&nbsp;s | β⁺ | ⁹³Tc | (9/2)+ | | |-id=Ruthenium-93m1 | rowspan=3 style="text-indent:1em" | ^93m1Ru | rowspan=3 colspan="3" style="text-indent:2em" | 734.40(10)&nbsp;keV | rowspan=3|10.8(3)&nbsp;s | β⁺ (78.0%) | ⁹³Tc | rowspan=3|(1/2)− | rowspan=3| | rowspan=3| |- | IT (22.0%) | ⁹³Ru |- | β⁺, p (0.027%) | ⁹²Mo |-id=Ruthenium-93m2 | style="text-indent:1em" | ^93m2Ru | colspan="3" style="text-indent:2em" | 2082.5(9)&nbsp;keV | 2.30(7)&nbsp;μs | IT | ⁹³Ru | (21/2)+ | | |-id=Ruthenium-94 | ⁹⁴Ru | style="text-align:right" | 44 | style="text-align:right" | 50 | 93.9113429(34) | 51.8(6)&nbsp;min | β⁺ | ⁹⁴Tc | 0+ | | |-id=Ruthenium-94m | style="text-indent:1em" | ^94mRu | colspan="3" style="text-indent:2em" | 2644.1(4)&nbsp;keV | 67.5(28)&nbsp;μs | IT | ⁹⁴Ru | 8+ | | |-id=Ruthenium-95 | ⁹⁵Ru | style="text-align:right" | 44 | style="text-align:right" | 51 | 94.910404(10) | 1.607(4)&nbsp;h | β⁺ | ⁹⁵Tc | 5/2+ | | |-id=Ruthenium-96 | ⁹⁶Ru | style="text-align:right" | 44 | style="text-align:right" | 52 | 95.90758891(18) | colspan=3 align=center|Observationally Stable | 0+ | 0.0554(14) | |-id=Ruthenium-97 | ⁹⁷Ru | style="text-align:right" | 44 | style="text-align:right" | 53 | 96.9075458(30) | 2.8370(14)&nbsp;d | β⁺ | ⁹⁷Tc | 5/2+ | | |-id=Ruthenium-98 | ⁹⁸Ru | style="text-align:right" | 44 | style="text-align:right" | 54 | 97.9052867(69) | colspan=3 align=center|Stable | 0+ | 0.0187(3) | |-id=Ruthenium-99 | ⁹⁹Ru | style="text-align:right" | 44 | style="text-align:right" | 55 | 98.90593028(37) | colspan=3 align=center|Stable | 5/2+ | 0.1276(14) | |-id=Ruthenium-100 | ¹⁰⁰Ru | style="text-align:right" | 44 | style="text-align:right" | 56 | 99.90421046(37) | colspan=3 align=center|Stable | 0+ | 0.1260(7) | |-id=Ruthenium-101 | ¹⁰¹Ru | style="text-align:right" | 44 | style="text-align:right" | 57 | 100.90557309(44) | colspan=3 align=center|Stable | 5/2+ | 0.1706(2) | |-id=Ruthenium-101m | style="text-indent:1em" | ^101mRu | colspan="3" style="text-indent:2em" | 527.56(10)&nbsp;keV | 17.5(4)&nbsp;μs | IT | ¹⁰¹Ru | 11/2− | | |-id=Ruthenium-102 | ¹⁰²Ru | style="text-align:right" | 44 | style="text-align:right" | 58 | 101.90434031(45) | colspan=3 align=center|Stable | 0+ | 0.3155(14) | |-id=Ruthenium-103 | ¹⁰³Ru | style="text-align:right" | 44 | style="text-align:right" | 59 | 102.90631485(47) | 39.245(8)&nbsp;d | β^− | ¹⁰³Rh | 3/2+ | | |-id=Ruthenium-103m | style="text-indent:1em" | ^103mRu | colspan="3" style="text-indent:2em" | 238.2(7)&nbsp;keV | 1.69(7)&nbsp;ms | IT | ¹⁰³Ru | 11/2− | | |-id=Ruthenium-104 | ¹⁰⁴Ru | style="text-align:right" | 44 | style="text-align:right" | 60 | 103.9054253(27) | colspan=3 align=center|Observationally Stable | 0+ | 0.1862(27) | |-id=Ruthenium-105 | ¹⁰⁵Ru | style="text-align:right" | 44 | style="text-align:right" | 61 | 104.9077455(27) | 4.439(11)&nbsp;h | β^− | ¹⁰⁵Rh | 3/2+ | | |-id=Ruthenium-105m | style="text-indent:1em" | ^105mRu | colspan="3" style="text-indent:2em" | 20.606(14)&nbsp;keV | 340(15)&nbsp;ns | IT | ¹⁰⁵Ru | 5/2+ | | |-id=Ruthenium-106 | ¹⁰⁶Ru | style="text-align:right" | 44 | style="text-align:right" | 62 | 105.9073282(58) | 371.8(18)&nbsp;d | β^− | ¹⁰⁶Rh | 0+ | | |-id=Ruthenium-107 | ¹⁰⁷Ru | style="text-align:right" | 44 | style="text-align:right" | 63 | 106.9099698(93) | 3.75(5)&nbsp;min | β^− | ¹⁰⁷Rh | (5/2)+ | | |-id=Ruthenium-108 | ¹⁰⁸Ru | style="text-align:right" | 44 | style="text-align:right" | 64 | 107.9101858(93) | 4.55(5)&nbsp;min | β^− | ¹⁰⁸Rh | 0+ | | |-id=Ruthenium-109 | ¹⁰⁹Ru | style="text-align:right" | 44 | style="text-align:right" | 65 | 108.9133237(96) | 34.4(2)&nbsp;s | β^− | ¹⁰⁹Rh | (5/2+) | | |-id=Ruthenium-109m | style="text-indent:1em" | ^109mRu | colspan="3" style="text-indent:2em" | 96.14(15)&nbsp;keV | 680(30)&nbsp;ns | IT | ¹⁰⁹Ru | (5/2−) | | |-id=Ruthenium-110 | ¹¹⁰Ru | style="text-align:right" | 44 | style="text-align:right" | 66 | 109.9140385(96) | 12.04(17)&nbsp;s | β^− | ¹¹⁰Rh | 0+ | | |-id=Ruthenium-111 | ¹¹¹Ru | style="text-align:right" | 44 | style="text-align:right" | 67 | 110.917568(10) | 2.12(7)&nbsp;s | β^− | ¹¹¹Rh | 5/2+ | | |-id=Ruthenium-112 | ¹¹²Ru | style="text-align:right" | 44 | style="text-align:right" | 68 | 111.918807(10) | 1.75(7)&nbsp;s | β^− | ¹¹²Rh | 0+ | | |-id=Ruthenium-113 | ¹¹³Ru | style="text-align:right" | 44 | style="text-align:right" | 69 | 112.922847(41) | 0.80(5)&nbsp;s | β^− | ¹¹³Rh | (1/2+) | | |-id=Ruthenium-113m | rowspan=2 style="text-indent:1em" | ^113mRu | rowspan=2 colspan="3" style="text-indent:2em" | 131(33)&nbsp;keV | rowspan=2|510(30)&nbsp;ms | β^− (?%) | ¹¹³Rh | rowspan=2|(7/2−) | rowspan=2| | rowspan=2| |- | IT (?%) | ¹¹³Ru |-id=Ruthenium-114 | rowspan=3|¹¹⁴Ru | rowspan=3 style="text-align:right" | 44 | rowspan=3 style="text-align:right" | 70 | rowspan=3|113.9246144(38) | rowspan=3|0.54(3)&nbsp;s | β^− | ¹¹⁴Rh | rowspan=3|0+ | rowspan=3| | rowspan=3| |- | β^-, n? | ¹¹³Rh |- | β^-, 2n? | ¹¹²Rh |-id=Ruthenium-115 | rowspan=2|¹¹⁵Ru | rowspan=2 style="text-align:right" | 44 | rowspan=2 style="text-align:right" | 71 | rowspan=2|114.929033(27) | rowspan=2|318(19)&nbsp;ms | β^− | ¹¹⁵Rh | rowspan=2|(1/2+) | rowspan=2| | rowspan=2| |- | β^-, n? | ¹¹⁴Rh |-id=Ruthenium-115m | rowspan=2 style="text-indent:1em" | ^115mRu | rowspan=2 colspan="3" style="text-indent:2em" | 82(6)&nbsp;keV | rowspan=2|76(6)&nbsp;ms | β^− (?%) | ¹¹⁵Rh | rowspan=2|(7/2−) | rowspan=2| | rowspan=2| |- | IT (?%) | ¹¹⁵Ru |-id=Ruthenium-116 | rowspan=2|¹¹⁶Ru | rowspan=2 style="text-align:right" | 44 | rowspan=2 style="text-align:right" | 72 | rowspan=2|115.9312192(40) | rowspan=2|204(6)&nbsp;ms | β^− | ¹¹⁶Rh | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β^-, n? | ¹¹⁵Rh |-id=Ruthenium-117 | rowspan=2|¹¹⁷Ru | rowspan=2 style="text-align:right" | 44 | rowspan=2 style="text-align:right" | 73 | rowspan=2|116.93614(47) | rowspan=2|151(3)&nbsp;ms | β^− | ¹¹⁷Rh | rowspan=2|3/2+# | rowspan=2| | rowspan=2| |- | β^-, n? | ¹¹⁶Rh |-id=Ruthenium-117m | style="text-indent:1em" | ^117mRu | colspan="3" style="text-indent:2em" | 185.0(4)&nbsp;keV | 2.49(6)&nbsp;μs | IT | ¹¹⁷Ru | 7/2−# | | |-id=Ruthenium-118 | rowspan=2|¹¹⁸Ru | rowspan=2 style="text-align:right" | 44 | rowspan=2 style="text-align:right" | 74 | rowspan=2|117.93881(22)# | rowspan=2|99(3)&nbsp;ms | β^− | ¹¹⁸Rh | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β^-, n? | ¹¹⁷Rh |-id=Ruthenium-119 | rowspan=3|¹¹⁹Ru | rowspan=3 style="text-align:right" | 44 | rowspan=3 style="text-align:right" | 75 | rowspan=3|118.94409(32)# | rowspan=3|69.5(20)&nbsp;ms | β^− | ¹¹⁹Rh | rowspan=3|3/2+# | rowspan=3| | rowspan=3| |- | β^-, n? | ¹¹⁸Rh |- | β^-, 2n? | ¹¹⁷Rh |-id=Ruthenium-119m | style="text-indent:1em" | ^119mRu | colspan="3" style="text-indent:2em" | 227.1(7)&nbsp;keV | 384(22)&nbsp;ns | IT | ¹¹⁹Ru | | | |-id=Ruthenium-120 | ¹²⁰Ru | style="text-align:right" | 44 | style="text-align:right" | 76 | 119.94662(43)# | 45(2)&nbsp;ms | β^− | ¹²⁰Rh | 0+ | | |-id=Ruthenium-121 | ¹²¹Ru | style="text-align:right" | 44 | style="text-align:right" | 77 | 120.95210(43)# | 29(2)&nbsp;ms | β^− | ¹²¹Rh | 3/2+# | | |-id=Ruthenium-122 | ¹²²Ru | style="text-align:right" | 44 | style="text-align:right" | 78 | 121.95515(54)# | 25(1)&nbsp;ms | β^− | ¹²²Rh | 0+ | | |-id=Ruthenium-123 | ¹²³Ru | style="text-align:right" | 44 | style="text-align:right" | 79 | 122.96076(54)# | 19(2)&nbsp;ms | β^− | ¹²³Rh | 3/2+# | | |-id=Ruthenium-124 | ¹²⁴Ru | style="text-align:right" | 44 | style="text-align:right" | 80 | 123.96394(64)# | 15(3)&nbsp;ms | β^− | ¹²⁴Rh | 0+ | | |-id=Ruthenium-125 | ¹²⁵Ru | style="text-align:right" | 44 | style="text-align:right" | 81 | 124.96954(32)# | 12#&nbsp;ms[>&nbsp;550&nbsp;ns] | | | 3/2+# | |

Alleged ruthenium-106 leak

In September 2017 an estimated amount of 100 to 300 TBq (0.3 to 1 g) of ¹⁰⁶Ru was released in Russia, probably in the Ural region. It was, after ruling out release from a reentering satellite, concluded that the source was either in nuclear fuel cycle facilities or radioactive source production. In France levels up to 0.036mBq/m³ of air were measured. It was estimated that for distances of the order of a few tens of kilometres, contamination levels may have exceeded the limits for non-dairy foodstuffs.

Asteroid that ended the Cretaceous period

The ratios of the amounts of ruthenium isotopes were used to determine the age of the asteroid which exterminated the dinosaurs at the end of the Cretaceous period, and to show that it originated beyond Jupiter in the outer solar system.

See also

Daughter products other than ruthenium

• Isotopes of rhodium
• Isotopes of technetium
• Isotopes of molybdenum

References