Naturally occurring
ruthenium
Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemical ...
(
44Ru) is composed of seven stable
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. Additionally, 27 radioactive isotopes have been discovered. Of these
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 ...
s, the most stable are
106Ru, 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 373.59 days;
103Ru, with a half-life of 39.26 days and
97Ru, with a half-life of 2.9 days.
Twenty-four other radioisotopes have been characterized with
atomic weight
Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a giv ...
s ranging from 86.95
u (
87Ru) to 119.95 u (
120Ru). Most of these have half-lives that are less than five minutes, except
94Ru (half-life: 51.8 minutes),
95Ru (half-life: 1.643 hours), and
105Ru (half-life: 4.44 hours).
The primary
decay mode before the most abundant isotope,
102Ru, is
electron capture
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Thi ...
and the primary mode after is
beta emission
In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For exam ...
. The primary
decay product before
102Ru is
technetium
Technetium is a chemical element with the symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. All available technetium is produced as a synthetic element. Naturally occurring technetium is a spontaneous ...
and the primary product after is
rhodium
Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a very rare, silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring i ...
.
Because of the very high volatility of
ruthenium tetroxide () ruthenium radioactive isotopes with their relative short half-life are considered as the second most hazardous gaseous isotopes after
iodine-131
Iodine-131 (131I, I-131) is an important radioisotope of iodine discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley. It has a radioactive decay half-life of about eight days. It is associated with nu ...
in case of release by a nuclear accident.
[Ronneau, C., Cara, J., & Rimski-Korsakov, A. (1995)]
Oxidation-enhanced emission of ruthenium from nuclear fuel
Journal of Environmental Radioactivity, 26(1), 63-70.[Backman, U., Lipponen, M., Auvinen, A., Jokiniemi, J., & Zilliacus, R. (2004)]
Ruthenium behaviour in severe nuclear accident conditions
Final report (No. NKS–100). Nordisk Kernesikkerhedsforskning.[Beuzet, E., Lamy, J. S., Perron, H., Simoni, E., & Ducros, G. (2012)]
Ruthenium release modelling in air and steam atmospheres under severe accident conditions using the MAAP4 code
Nuclear Engineering and Design, 246, 157-162. The two most important isotopes of ruthenium in case of nuclear accident are these with the longest half-life:
103Ru (≥ 1 month) and
106Ru (≥ 1 year).
List of isotopes
, -
,
87Ru
, style="text-align:right" , 44
, style="text-align:right" , 43
, 86.94918(64)#
, 50# ms
1.5 µs,
β+
,
87Tc
, 1/2−#
,
,
, -
,
88Ru
, style="text-align:right" , 44
, style="text-align:right" , 44
, 87.94026(43)#
, 1.3(3) s
.2(+3−2) s, β
+
,
88Tc
, 0+
,
,
, -
,
89Ru
, style="text-align:right" , 44
, style="text-align:right" , 45
, 88.93611(54)#
, 1.38(11) s
, β
+
,
89Tc
, (7/2)(+#)
,
,
, -
,
90Ru
, style="text-align:right" , 44
, style="text-align:right" , 46
, 89.92989(32)#
, 11.7(9) s
, β
+
,
90Tc
, 0+
,
,
, -
,
91Ru
, style="text-align:right" , 44
, style="text-align:right" , 47
, 90.92629(63)#
, 7.9(4) s
, β
+
,
91Tc
, (9/2+)
,
,
, -
, rowspan=3 style="text-indent:1em" ,
91mRu
, rowspan=3 colspan="3" style="text-indent:2em" , 80(300)# keV
, rowspan=3, 7.6(8) s
, β
+ (>99.9%)
,
91Tc
, rowspan=3, (1/2−)
, rowspan=3,
, rowspan=3,
, -
,
IT (<.1%)
,
91Ru
, -
, β
+,
p (<.1%)
,
90Mo
, -
,
92Ru
, style="text-align:right" , 44
, style="text-align:right" , 48
, 91.92012(32)#
, 3.65(5) min
, β
+
,
92Tc
, 0+
,
,
, -
,
93Ru
, style="text-align:right" , 44
, style="text-align:right" , 49
, 92.91705(9)
, 59.7(6) s
, β
+
,
93Tc
, (9/2)+
,
,
, -
, rowspan=3 style="text-indent:1em" ,
93m1Ru
, rowspan=3 colspan="3" style="text-indent:2em" , 734.40(10) keV
, rowspan=3, 10.8(3) s
, β
+ (78%)
,
93Tc
, rowspan=3, (1/2)−
, rowspan=3,
, rowspan=3,
, -
, IT (22%)
,
93Ru
, -
, β
+, p (.027%)
,
92Mo
, -
, style="text-indent:1em" ,
93m2Ru
, colspan="3" style="text-indent:2em" , 2082.6(9) keV
, 2.20(17) µs
,
,
, (21/2)+
,
,
, -
,
94Ru
, style="text-align:right" , 44
, style="text-align:right" , 50
, 93.911360(14)
, 51.8(6) min
, β
+
,
94Tc
, 0+
,
,
, -
, style="text-indent:1em" ,
94mRu
, colspan="3" style="text-indent:2em" , 2644.55(25) keV
, 71(4) µs
,
,
, (8+)
,
,
, -
,
95Ru
, style="text-align:right" , 44
, style="text-align:right" , 51
, 94.910413(13)
, 1.643(14) h
, β
+
,
95Tc
, 5/2+
,
,
, -
,
96Ru
, style="text-align:right" , 44
, style="text-align:right" , 52
, 95.907598(8)
, colspan=3 align=center,
Observationally Stable
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes.
Th ...
[Believed to undergo β+β+ decay to 96Mo with a half-life over 6.7×1016 years]
, 0+
, 0.0554(14)
,
, -
,
97Ru
, style="text-align:right" , 44
, style="text-align:right" , 53
, 96.907555(9)
, 2.791(4) d
, β
+
,
97mTc
, 5/2+
,
,
, -
,
98Ru
, style="text-align:right" , 44
, style="text-align:right" , 54
, 97.905287(7)
, colspan=3 align=center, Stable
[Theoretically capable of spontaneous fission]
, 0+
, 0.0187(3)
,
, -
,
99Ru
, style="text-align:right" , 44
, style="text-align:right" , 55
, 98.9059393(22)
, colspan=3 align=center, Stable
, 5/2+
, 0.1276(14)
,
, -
,
100Ru
, style="text-align:right" , 44
, style="text-align:right" , 56
, 99.9042195(22)
, colspan=3 align=center, Stable
, 0+
, 0.1260(7)
,
, -
,
101Ru
[ Fission product]
, style="text-align:right" , 44
, style="text-align:right" , 57
, 100.9055821(22)
, colspan=3 align=center, Stable
, 5/2+
, 0.1706(2)
,
, -
, style="text-indent:1em" ,
101mRu
, colspan="3" style="text-indent:2em" , 527.56(10) keV
, 17.5(4) µs
,
,
, 11/2−
,
,
, -
,
102Ru
, style="text-align:right" , 44
, style="text-align:right" , 58
, 101.9043493(22)
, colspan=3 align=center, Stable
, 0+
, 0.3155(14)
,
, -
,
103Ru
, style="text-align:right" , 44
, style="text-align:right" , 59
, 102.9063238(22)
, 39.26(2) d
, β
−
,
103Rh
, 3/2+
,
,
, -
, style="text-indent:1em" ,
103mRu
, colspan="3" style="text-indent:2em" , 238.2(7) keV
, 1.69(7) ms
, IT
,
103Ru
, 11/2−
,
,
, -
,
104Ru
, style="text-align:right" , 44
, style="text-align:right" , 60
, 103.905433(3)
, colspan=3 align=center, Observationally Stable
[Believed to undergo β−β− decay to 104Pd]
, 0+
, 0.1862(27)
,
, -
,
105Ru
, style="text-align:right" , 44
, style="text-align:right" , 61
, 104.907753(3)
, 4.44(2) h
, β
−
,
105Rh
, 3/2+
,
,
, -
,
106Ru
, style="text-align:right" , 44
, style="text-align:right" , 62
, 105.907329(8)
, 373.59(15) d
, β
−
,
106Rh
, 0+
,
,
, -
,
107Ru
, style="text-align:right" , 44
, style="text-align:right" , 63
, 106.90991(13)
, 3.75(5) min
, β
−
,
107Rh
, (5/2)+
,
,
, -
,
108Ru
, style="text-align:right" , 44
, style="text-align:right" , 64
, 107.91017(12)
, 4.55(5) min
, β
−
,
108Rh
, 0+
,
,
, -
,
109Ru
, style="text-align:right" , 44
, style="text-align:right" , 65
, 108.91320(7)
, 34.5(10) s
, β
−
,
109Rh
, (5/2+)#
,
,
, -
,
110Ru
, style="text-align:right" , 44
, style="text-align:right" , 66
, 109.91414(6)
, 11.6(6) s
, β
−
,
110Rh
, 0+
,
,
, -
,
111Ru
, style="text-align:right" , 44
, style="text-align:right" , 67
, 110.91770(8)
, 2.12(7) s
, β
−
,
111Rh
, (5/2+)
,
,
, -
,
112Ru
, style="text-align:right" , 44
, style="text-align:right" , 68
, 111.91897(8)
, 1.75(7) s
, β
−
,
112Rh
, 0+
,
,
, -
,
113Ru
, style="text-align:right" , 44
, style="text-align:right" , 69
, 112.92249(8)
, 0.80(5) s
, β
−
,
113Rh
, (5/2+)
,
,
, -
, style="text-indent:1em" ,
113mRu
, colspan="3" style="text-indent:2em" , 130(18) keV
, 510(30) ms
,
,
, (11/2−)
,
,
, -
, rowspan=2,
114Ru
, rowspan=2 style="text-align:right" , 44
, rowspan=2 style="text-align:right" , 70
, rowspan=2, 113.92428(25)#
, rowspan=2, 0.53(6) s
, β
− (>99.9%)
,
114Rh
, rowspan=2, 0+
, rowspan=2,
, rowspan=2,
, -
, β
−,
n (<.1%)
,
113Rh
, -
, rowspan=2,
115Ru
, rowspan=2 style="text-align:right" , 44
, rowspan=2 style="text-align:right" , 71
, rowspan=2, 114.92869(14)
, rowspan=2, 740(80) ms
, β
− (>99.9%)
,
115Rh
, rowspan=2,
, rowspan=2,
, rowspan=2,
, -
, β
−, n (<.1%)
,
114Rh
, -
,
116Ru
, style="text-align:right" , 44
, style="text-align:right" , 72
, 115.93081(75)#
, 400# ms
300 ns, β
−
,
116Rh
, 0+
,
,
, -
,
117Ru
, style="text-align:right" , 44
, style="text-align:right" , 73
, 116.93558(75)#
, 300# ms
300 ns, β
−
,
117Rh
,
,
,
, -
,
118Ru
, style="text-align:right" , 44
, style="text-align:right" , 74
, 117.93782(86)#
, 200# ms
300 ns, β
−
,
118Rh
, 0+
,
,
, -
,
119Ru
, style="text-align:right" , 44
, style="text-align:right" , 75
, 118.94284(75)#
, 170# ms
300 ns,
,
,
,
,
, -
,
120Ru
, style="text-align:right" , 44
, style="text-align:right" , 76
, 119.94531(86)#
, 80# ms
300 ns,
,
, 0+
,
,
* Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the
atomic mass
The atomic mass (''m''a or ''m'') is the mass of an atom. Although the SI unit of mass is the kilogram (symbol: kg), atomic mass is often expressed in the non-SI unit dalton (symbol: Da) – equivalently, unified atomic mass unit (u). 1&nb ...
may exceed the stated value for such specimens.
* 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 is to be found either in nuclear fuel cycle facilities or radioactive source production. In France levels up to 0.036mBq/m
3 of air were measured. It is estimated that over distances of the order of a few tens of kilometres around the location of the release levels may exceed the limits for non-dairy foodstuffs.
Detection of ruthenium 106 in France and in Europe, IRSN France (9 Nov 2017)
References
* Isotope masses from:
**
* Isotopic compositions and standard atomic masses from:
**
**
* Half-life, spin, and isomer data selected from the following sources.
**
**
**
{{Navbox element isotopes
Isotopes of ruthenium,
Ruthenium
Ruthenium
Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemical ...