Naturally occurring ruthenium

Ruthenium

Ruthenium is a chemical element with 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 chemicals. The Russian scientist Karl Ernst Claus discovered the element...

(Ru) is composed of seven stable isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are ¹⁰⁶Ru with a half-life

Half-life

Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 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

Atomic weight

Atomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...

s ranging from 86.95 u (⁸⁷Ru) to 119.95 u (¹²⁰Ru). Most of these have half-lives that are less than five minutes, excepting 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

Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...

 and the primary mode after is beta emission. The primary decay product

Decay product

In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...

 before ¹⁰²Ru is technetium

Technetium

Technetium is the chemical element with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature...

 and the primary mode after is rhodium

Rhodium

Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...

.

Standard atomic mass: 101.07(2) u

Table

nuclide symbol	Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... )	N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... )	isotopic mass (u)	half-life	decay mode(s)Abbreviations: IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....	daughter isotope(s)Bold for stable isotopes	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
87Ru	44	43	86.94918(64)#	50# ms [>1.5 µs]	β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...	87Tc	1/2-#
88Ru	44	44	87.94026(43)#	1.3(3) s [1.2(+3-2) s]	β+	88Tc	0+
89Ru	44	45	88.93611(54)#	1.38(11) s	β+	89Tc	(7/2)(+#)
90Ru	44	46	89.92989(32)#	11.7(9) s	β+	90Tc	0+
91Ru	44	47	90.92629(63)#	7.9(4) s	β+	91Tc	(9/2+)
91mRu	80(300)# keV			7.6(8) s	β+ (>99.9%)	91Tc	(1/2-)
					IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....  (<.1%)	91Ru
					β+, p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very...  (<.1%)	90Mo
92Ru	44	48	91.92012(32)#	3.65(5) min	β+	92Tc	0+
93Ru	44	49	92.91705(9)	59.7(6) s	β+	93Tc	(9/2)+
93m1Ru	734.40(10) keV			10.8(3) s	β+ (78%)	93Tc	(1/2)-
					IT (22%)	93Ru
					β+, p (.027%)	92Mo
93m2Ru	2082.6(9) keV			2.20(17) µs			(21/2)+
94Ru	44	50	93.911360(14)	51.8(6) min	β+	94Tc	0+
94mRu	2644.55(25) keV			71(4) µs			(8+)
95Ru	44	51	94.910413(13)	1.643(14) h	β+	95Tc	5/2+
96Ru	44	52	95.907598(8)	Observationally StableBelieved to undergo β+β+ decay to 96Mo with a half-life over 67×1015 years			0+	0.0554(14)
97Ru	44	53	96.907555(9)	2.791(4) d	β+	97mTc	5/2+
98Ru	44	54	97.905287(7)	Observationally StableTheoretically capable of spontaneous fission Spontaneous fission Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses...			0+	0.0187(3)
99Ru	44	55	98.9059393(22)	Observationally Stable			5/2+	0.1276(14)
100Ru	44	56	99.9042195(22)	Observationally Stable			0+	0.1260(7)
101RuFission product Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The...	44	57	100.9055821(22)	Observationally Stable			5/2+	0.1706(2)
101mRu	527.56(10) keV			17.5(4) µs			11/2-
102Ru	44	58	101.9043493(22)	Observationally Stable			0+	0.3155(14)
103Ru	44	59	102.9063238(22)	39.26(2) d	β-	103Rh	3/2+
103mRu	238.2(7) keV			1.69(7) ms	IT	103Ru	11/2-
104Ru	44	60	103.905433(3)	Observationally StableBelieved to undergo β-β- decay to 104Pd			0+	0.1862(27)
105Ru	44	61	104.907753(3)	4.44(2) h	β-	105Rh	3/2+
106Ru	44	62	105.907329(8)	373.59(15) d	β-	106Rh	0+
107Ru	44	63	106.90991(13)	3.75(5) min	β-	107Rh	(5/2)+
108Ru	44	64	107.91017(12)	4.55(5) min	β-	108Rh	0+
109Ru	44	65	108.91320(7)	34.5(10) s	β-	109Rh	(5/2+)#
110Ru	44	66	109.91414(6)	11.6(6) s	β-	110Rh	0+
111Ru	44	67	110.91770(8)	2.12(7) s	β-	111Rh	(5/2+)
112Ru	44	68	111.91897(8)	1.75(7) s	β-	112Rh	0+
113Ru	44	69	112.92249(8)	0.80(5) s	β-	113Rh	(5/2+)
113mRu	130(18) keV			510(30) ms			(11/2-)
114Ru	44	70	113.92428(25)#	0.53(6) s	β- (>99.9%)	114Rh	0+
					β-, n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13... (<.1%)	113Rh
115Ru	44	71	114.92869(14)	740(80) ms	β- (>99.9%)	115Rh
					β-, n (<..1%)	114Rh
116Ru	44	72	115.93081(75)#	400# ms [>300 ns]	β-	116Rh	0+
117Ru	44	73	116.93558(75)#	300# ms [>300 ns]	β-	117Rh
118Ru	44	74	117.93782(86)#	200# ms [>300 ns]	β-	118Rh	0+
119Ru	44	75	118.94284(75)#	170# ms [>300 ns]
120Ru	44	76	119.94531(86)#	80# ms [>300 ns]			0+

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