Isotopes of rhodium

Isotopes of rhodium (₄₅Rh)
IT	101Rh
β−	102Pd
IT	102Rh
Standard atomic weight Ar°(Rh)
	102.90549±0.00002; 102.91±0.01 (abridged);
	view ; talk ; edit ;

Last updated October 11, 2024

Naturally occurring rhodium (₄₅Rh) is composed of only one stable isotope, ¹⁰³Rh.^[4] The most stable radioisotopes are ¹⁰¹Rh with a half-life of 3.3 years, ¹⁰²Rh with a half-life of 207 days, and ⁹⁹Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (⁸⁹Rh) to 121.943 u (¹²²Rh). Most of these have half-lives that are less than an hour except ¹⁰⁰Rh (half-life: 20.8 hours) and ¹⁰⁵Rh (half-life: 35.36 hours). There are also numerous meta states with the most stable being ^102mRh (0.141 MeV) with a half-life of about 3.7 years and ^101mRh (0.157 MeV) with a half-life of 4.34 days.

The primary decay mode before the only stable isotope, ¹⁰³Rh, is electron capture and the primary mode after is beta emission. The primary decay product before ¹⁰³Rh is ruthenium and the primary product after is palladium.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[5] ^{[n 2]}^{[n 3]}	Half-life ^[1] ^{[n 4]}	Decay mode ^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^[1] ^{[n 7]}^{[n 4]}	Isotopic abundance
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life ^[1] ^{[n 4]}	Decay mode ^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^[1] ^{[n 7]}^{[n 4]}	Isotopic abundance
⁹⁰Rh	45	45	89.94457(22)#	29(3) ms	β⁺	⁹⁰Ru	(0+)
⁹⁰Rh	45	45	89.94457(22)#	29(3) ms	β⁺, p? (<0.7%)	⁸⁹Tc	(0+)
^90mRh^{[n 8]}	0(500)# keV			0.56(2) s	β⁺ (90.4%)	⁹⁰Ru	(7+)
^90mRh^{[n 8]}	0(500)# keV			0.56(2) s	β⁺, p (9.6%)	⁸⁹Tc	(7+)
⁹¹Rh	45	46	90.93712(32)#	1.47(22) s	β⁺ (98.7%)	⁹¹Ru	(9/2+)
⁹¹Rh	45	46	90.93712(32)#	1.47(22) s	β⁺, p (1.3%)	⁹⁰Tc	(9/2+)
^91mRh	172.9(4) keV			1.8# s	β⁺?	⁹¹Ru	1/2−#
					β⁺, p?	⁹⁰Tc
					IT?	⁹¹Rh
⁹²Rh	45	47	91.9323677(47)	5.61(8) s	β⁺ (97.95%)	⁹²Ru	(6+)
⁹²Rh	45	47	91.9323677(47)	5.61(8) s	β⁺, p (2.05%)	⁹¹Tc	(6+)
^92m1Rh	50(100)# keV			3.18(22) s	β⁺ (98.3%)	⁹²Ru	(2+)
^92m1Rh	50(100)# keV			3.18(22) s	β⁺, p (1.7%)	⁹¹Tc	(2+)
^92m2Rh	105(100)# keV			232(15) ns	IT	⁹²Rh	(4+)
⁹³Rh	45	48	92.9259128(28)	13.9(16) s	β⁺	⁹³Ru	9/2+#
⁹⁴Rh	45	49	93.9217305(36)	70.6(6) s	β⁺ (98.2%)	⁹⁴Ru	(4+)
⁹⁴Rh	45	49	93.9217305(36)	70.6(6) s	β⁺, p (1.8%)	⁹³Tc	(4+)
^94m1Rh	54.60(20)# keV			480(30) ns	IT	⁹⁴Rh	(2+)
^94m2Rh^{[n 8]}	300(200)# keV			25.8(2) s	β⁺	⁹⁴Ru	(8+)
⁹⁵Rh	45	50	94.9158979(42)	5.02(10) min	β⁺	⁹⁵Ru	(9/2)+
^95mRh	543.3(3) keV			1.96(4) min	IT (88%)	⁹⁵Rh	(1/2)−
^95mRh	543.3(3) keV			1.96(4) min	β⁺ (12%)	⁹⁵Ru	(1/2)−
⁹⁶Rh	45	51	95 914452(11)	9.90(10) min	β⁺	⁹⁶Ru	6+
^96mRh	51.98(9) keV			1.51(2) min	IT (60%)	⁹⁶Rh	3+
^96mRh	51.98(9) keV			1.51(2) min	β⁺ (40%)	⁹⁶Ru	3+
⁹⁷Rh	45	52	96.911328(38)	30.7(6) min	β⁺	⁹⁷Ru	9/2+
^97mRh	258.76(18) keV			46.2(16) min	β⁺ (94.4%)	⁹⁷Ru	1/2−
^97mRh	258.76(18) keV			46.2(16) min	IT (5.6%)	⁹⁷Rh	1/2−
⁹⁸Rh	45	53	97.910708(13)	8.72(12) min	β⁺	⁹⁸Ru	(2)+
^98mRh^{[n 8]}	56.3(10) keV			3.6(2) min	IT (89%)	⁹⁸Rh	(5+)
^98mRh^{[n 8]}	56.3(10) keV			3.6(2) min	β⁺ (11%)	⁹⁸Ru	(5+)
⁹⁹Rh	45	54	98.908121(21)	16.1(2) d	β⁺	⁹⁹Ru	1/2−
^99mRh	64.4(5) keV			4.7(1) h	β⁺	⁹⁹Ru	9/2+
^99mRh	64.4(5) keV			4.7(1) h	IT?	⁹⁹Rh	9/2+
¹⁰⁰Rh	45	55	99.908114(19)	20.8(1) h	EC (95.1%)	¹⁰⁰Ru	1−
¹⁰⁰Rh	45	55	99.908114(19)	20.8(1) h	β⁺ (4.9%)	¹⁰⁰Ru	1−
^100m1Rh	74.782(14) keV			214.0(20) ns	IT	¹⁰⁰Rh	(2)+
^100m2Rh	107.6(2) keV			4.6(2) min	IT (98.3%)	¹⁰⁰Rh	(5+)
^100m2Rh	107.6(2) keV			4.6(2) min	β⁺ (1.7%)	¹⁰⁰Ru	(5+)
^100m3Rh	219.61(22) keV			130(10) ns	IT	¹⁰⁰Rh	(7+)
¹⁰¹Rh	45	56	100.9061589(63)	4.07(5) y	EC	¹⁰¹Ru	1/2−
^101mRh	157.32(3) keV			4.343(10) d	EC (92.80%)	¹⁰¹Ru	9/2+
^101mRh	157.32(3) keV			4.343(10) d	IT (7.20%)	¹⁰¹Rh	9/2+
¹⁰²Rh	45	57	101.9068343(69)	207.0(15) d	β⁺ (78%)	¹⁰²Ru	2−
¹⁰²Rh	45	57	101.9068343(69)	207.0(15) d	β⁻ (22%)	¹⁰²Pd	2−
^102mRh	140.73(9) keV			3.742(10) y	β⁺ (99.77%)	¹⁰²Ru	6+
^102mRh	140.73(9) keV			3.742(10) y	IT (0.233%)	¹⁰²Rh	6+
¹⁰³Rh^{[n 9]}	45	58	102.9054941(25)	Stable			1/2−	1.0000
^103mRh	39.753(6) keV			56.114(9) min	IT	¹⁰³Rh	7/2+
¹⁰⁴Rh	45	59	103.9066453(25)	42.3(4) s	β⁻ (99.55%)	¹⁰⁴Pd	1+
¹⁰⁴Rh	45	59	103.9066453(25)	42.3(4) s	β⁺ (0.45%)	¹⁰⁴Ru	1+
^104mRh	128.9679(5) keV			4.34(3) min	IT (99.87%)	¹⁰⁴Rh	5+
^104mRh	128.9679(5) keV			4.34(3) min	β⁻ (0.13%)	¹⁰⁴Pd	5+
¹⁰⁵Rh^{[n 9]}	45	60	104.9056878(27)	35.341(19) h	β⁻	¹⁰⁵Pd	7/2+
^105mRh	129.742(4) keV			42.8(3) s	IT	¹⁰⁵Rh	1/2−
¹⁰⁶Rh	45	61	105.9072859(58)	30.07(35) s	β⁻	¹⁰⁶Pd	1+
^106mRh	132(11) keV			131(2) min	β⁻	¹⁰⁶Pd	(6)+
¹⁰⁷Rh	45	62	106.906748(13)	21.7(4) min	β⁻	¹⁰⁷Pd	7/2+
^107mRh	268.36(4) keV			>10 μs	IT	¹⁰⁷Rh	1/2−
¹⁰⁸Rh	45	63	107.908715(15)	16.8(5) s	β⁻	¹⁰⁸Pd	1+
^108mRh	115(18) keV			6.0(3) min	β⁻	¹⁰⁸Pd	(5+)
¹⁰⁹Rh	45	64	108.9087496(43)	80.8(7) s	β⁻	¹⁰⁹Pd	7/2+
^109mRh	225.873(19) keV			1.66(4) μs	IT	¹⁰⁹Pd	3/2+
¹¹⁰Rh	45	65	109.911080(19)	3.35(12) s	β⁻	¹¹⁰Pd	(1+)
^110mRh^{[n 8]}	220(150)# keV			28.5(13) s	β⁻	¹¹⁰Pd	(6+)
¹¹¹Rh	45	66	110.9116432(74)	11(1) s	β⁻	¹¹¹Pd	(7/2+)
¹¹²Rh	45	67	111.914405(47)	3.4(4) s	β⁻	¹¹²Pd	(1+)
^112mRh	340(70) keV			6.73(15) s	β⁻	¹¹²Pd	(6+)
¹¹³Rh	45	68	112.9154402(77)	2.80(12) s	β⁻	¹¹³Pd	(7/2+)
¹¹⁴Rh	45	69	113.918722(77)	1.85(5) s	β⁻	¹¹⁴Pd	1+
^114mRh^{[n 8]}	200(150)# keV			1.85(5) s	β⁻	¹¹⁴Pd	(7−)
¹¹⁵Rh	45	70	114.9203116(79)	1.03(3) s	β⁻	¹¹⁵Pd	(7/2+)
¹¹⁵Rh	45	70	114.9203116(79)	1.03(3) s	β⁻, n?	¹¹⁴Pd	(7/2+)
¹¹⁶Rh	45	71	115.924062(79)	685(39) ms	β⁻ (>97.9%)	¹¹⁶Pd	1+
¹¹⁶Rh	45	71	115.924062(79)	685(39) ms	β⁻, n? (<2.1%)	¹¹⁵Pd	1+
^116mRh^{[n 8]}	200(150)# keV			570(50) ms	β⁻ (>97.9%)	¹¹⁶Pd	(6−)
^116mRh^{[n 8]}	200(150)# keV			570(50) ms	β⁻, n? (<2.1%)	¹¹⁵Pd	(6−)
¹¹⁷Rh	45	72	116.9260363(95)	421(30) ms	β⁻	¹¹⁷Pd	7/2+#
¹¹⁷Rh	45	72	116.9260363(95)	421(30) ms	β⁻, n? (<7.6%)	¹¹⁵Pd	7/2+#
^117mRh	321.2(10) keV			138(17) ns	IT	¹¹⁷Rh	3/2+#
¹¹⁸Rh	45	73	117.930341(26)	282(9) ms	β⁻ (96.9%)	¹¹⁸Pd	1+#
¹¹⁸Rh	45	73	117.930341(26)	282(9) ms	β⁻, n (3.1%)	¹¹⁷Pd	1+#
^118mRh^{[n 8]}	200(150)# keV			310(30) ms	β⁻ (96.9%)	¹¹⁸Pd	6−#
					β⁻, n (3.1%)	¹¹⁷Pd
					IT?	¹¹⁸Rh
¹¹⁹Rh	45	74	118.932557(10)	190(6) ms	β⁻ (93.6%)	¹¹⁹Pd	7/2+#
¹¹⁹Rh	45	74	118.932557(10)	190(6) ms	β⁻, n (6.4%)	¹¹⁸Pd	7/2+#
¹²⁰Rh	45	75	119.93707(22)#	129.6(42) ms	β⁻	¹²⁰Pd	8−#
					β⁻, n (<9.3%)	¹¹⁹Pd
					β⁻, 2n?	¹¹⁸Pd
^120mRh	157.2(7) keV			295(16) ns	IT	¹²⁰Rh	6#
¹²¹Rh	45	76	120.93961(67)	74(4) ms	β⁻	¹²¹Pd	7/2+#
¹²¹Rh	45	76	120.93961(67)	74(4) ms	β⁻, n (>11%)	¹²⁰Pd	7/2+#
¹²²Rh	45	77	121.94431(32)#	51(6) ms	β⁻	¹²²Pd	7−#
					β⁻, n (<3.9%)	¹²¹Pd
					β⁻, 2n?	¹²⁰Pd
^122mRh	271.0(7) keV			830(120) ns	IT	¹²²Rh	4+#
¹²³Rh	45	78	122.94719(43)#	42(4) ms	β⁻	¹²³Pd	7/2+#
					β⁻, n (>24%)	¹²²Pd
					β⁻, 2n?	¹²¹Pd
¹²⁴Rh	45	79	123.95200(43)#	30(2) ms	β⁻	¹²⁴Pd	2+#
					β⁻, n (<31%)	¹²³Pd
					β⁻, 2n?	¹²²Pd
¹²⁵Rh	45	80	124.95509(54)#	26.5(20) ms	β⁻	¹²⁵Pd	7/2+#
					β⁻, n?	¹²⁴Pd
					β⁻, 2n?	¹²³Pd
¹²⁶Rh	45	81	125.96006(54)#	19(3) ms	β⁻	¹²⁶Pd	1−#
					β⁻, n?	¹²⁵Pd
					β⁻, 2n?	¹²⁴Pd
¹²⁷Rh	45	82	126.96379(64)#	28(14) ms	β⁻	¹²⁷Pd	7/2+#
					β⁻, n?	¹²⁶Pd
					β⁻, 2n?	¹²⁵Pd
¹²⁸Rh	45	83	127.97065(32)#	8# ms [>550 ns]	β⁻?	¹²⁸Pd
					β⁻, n?	¹²⁷Pd
					β⁻, 2n?	¹²⁶Pd
This table header & footer: view

↑ ^mRh – Excited nuclear isomer.
↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
↑ Modes of decay:
EC: Electron capture
IT: Isomeric transition
n: Neutron emission
p: Proton emission
↑ Bold symbol as daughter – Daughter product is stable.
↑ ( ) spin value – Indicates spin with weak assignment arguments.
1 2 3 4 5 6 7 Order of ground state and isomer is uncertain.
1 2 Fission product

Related Research Articles

Francium (₈₇Fr) has no stable isotopes. A standard atomic weight cannot be given. Its most stable isotope is ²²³Fr with a half-life of 22 minutes, occurring in trace quantities in nature as an intermediate decay product of ²³⁵U.

There are 39 known isotopes of radon (₈₆Rn), from ¹⁹³Rn to ²³¹Rn; all are radioactive. The most stable isotope is ²²²Rn with a half-life of 3.823 days, which decays into ²¹⁸
Po. Six isotopes of radon, ^{217, 218, 219, 220, 221, 222}Rn, occur in trace quantities in nature as decay products of, respectively, ²¹⁷At, ²¹⁸At, ²²³Ra, ²²⁴Ra, ²²⁵Ra, and ²²⁶Ra. ²¹⁷Rn and ²²¹Rn are produced in rare branches in the decay chain of trace quantities of ²³⁷Np; ²²²Rn is an intermediate step in the decay chain of ²³⁸U; ²¹⁹Rn is an intermediate step in the decay chain of ²³⁵U; and ²²⁰Rn occurs in the decay chain of ²³²Th.

There are 42 isotopes of polonium (₈₄Po). They range in size from 186 to 227 nucleons. They are all radioactive. ²¹⁰Po with a half-life of 138.376 days has the longest half-life of any naturally-occurring isotope of polonium and is the most common isotope of polonium. It is also the most easily synthesized polonium isotope. ²⁰⁹Po, which does not occur naturally, has the longest half-life of all isotopes of polonium at 124 years. ²⁰⁹Po can be made by using a cyclotron to bombard bismuth with protons, as can ²⁰⁸Po.

Thallium (₈₁Tl) has 41 isotopes with atomic masses that range from 176 to 216. ²⁰³Tl and ²⁰⁵Tl are the only stable isotopes and ²⁰⁴Tl is the most stable radioisotope with a half-life of 3.78 years. ²⁰⁷Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

Naturally occurring platinum (₇₈Pt) consists of five stable isotopes (¹⁹²Pt, ¹⁹⁴Pt, ¹⁹⁵Pt, ¹⁹⁶Pt, ¹⁹⁸Pt) and one very long-lived (half-life 4.83×10¹¹ years) radioisotope (¹⁹⁰Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is ¹⁹³Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.

Natural hafnium (₇₂Hf) consists of five observationally stable isotopes (¹⁷⁶Hf, ¹⁷⁷Hf, ¹⁷⁸Hf, ¹⁷⁹Hf, and ¹⁸⁰Hf) and one very long-lived radioisotope, ¹⁷⁴Hf, with a half-life of 7.0×10¹⁶ years. In addition, there are 34 known synthetic radioisotopes, the most stable of which is ¹⁸²Hf with a half-life of 8.9×10⁶ years. This extinct radionuclide is used in hafnium–tungsten dating to study the chronology of planetary differentiation.

Naturally occurring ytterbium (₇₀Yb) is composed of seven stable isotopes: ¹⁶⁸Yb, ¹⁷⁰Yb–¹⁷⁴Yb, and ¹⁷⁶Yb, with ¹⁷⁴Yb being the most abundant. 30 radioisotopes have been characterized, with the most stable being ¹⁶⁹Yb with a half-life of 32.014 days, ¹⁷⁵Yb with a half-life of 4.185 days, and ¹⁶⁶Yb with a half-life of 56.7 hours. All of the remaining radioactive isotopes have half-lives that are less than 2 hours, and the majority of these have half-lives that are less than 20 minutes. This element also has 18 meta states, with the most stable being ^169mYb.

Naturally occurring terbium (₆₅Tb) is composed of one stable isotope, ¹⁵⁹Tb. Thirty-seven radioisotopes have been characterized, with the most stable being ¹⁵⁸Tb with a half-life of 180 years, ¹⁵⁷Tb with a half-life of 71 years, and ¹⁶⁰Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states, with the most stable being ^156m1Tb, ^154m2Tb and ^154m1Tb.

Naturally occurring praseodymium (₅₉Pr) is composed of one stable isotope, ¹⁴¹Pr. Thirty-eight radioisotopes have been characterized with the most stable being ¹⁴³Pr, with a half-life of 13.57 days and ¹⁴²Pr, with a half-life of 19.12 hours. All of the remaining radioactive isotopes have half-lives that are less than 5.985 hours and the majority of these have half-lives that are less than 33 seconds. This element also has 15 meta states with the most stable being ^138mPr, ^142mPr and ^134mPr.

Naturally occurring cerium (₅₈Ce) is composed of 4 stable isotopes: ¹³⁶Ce, ¹³⁸Ce, ¹⁴⁰Ce, and ¹⁴²Ce, with ¹⁴⁰Ce being the most abundant and the only one theoretically stable; ¹³⁶Ce, ¹³⁸Ce, and ¹⁴²Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being ¹⁴⁴Ce, with a half-life of 284.893 days; ¹³⁹Ce, with a half-life of 137.640 days and ¹⁴¹Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.

Naturally occurring lanthanum (₅₇La) is composed of one stable (¹³⁹La) and one radioactive (¹³⁸La) isotope, with the stable isotope, ¹³⁹La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being ¹³⁸La, with a half-life of 1.02×10¹¹ years; ¹³⁷La, with a half-life of 60,000 years and ¹⁴⁰La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is ^132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. ¹³⁸La can decay to both.

Naturally occurring barium (₅₆Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×10²¹ years (about 10¹¹ times the age of the universe).

Antimony (₅₁Sb) occurs in two stable isotopes, ¹²¹Sb and ¹²³Sb. There are 37 artificial radioactive isotopes, the longest-lived of which are ¹²⁵Sb, with a half-life of 2.75856 years; ¹²⁴Sb, with a half-life of 60.2 days; and ¹²⁶Sb, with a half-life of 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour. There are also many isomers, the longest-lived of which is ^120m1Sb with a half-life of 5.76 days.

Natural yttrium (₃₉Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are ⁸⁸Y, which has a half-life of 106.6 days, and ⁹¹Y, with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except ⁸⁷Y, which has a half-life of 79.8 hours, and ⁹⁰Y, with 64 hours. The dominant decay mode below the stable ⁸⁹Y is electron capture and the dominant mode after it is beta emission. Thirty-five unstable isotopes have been characterized.

Arsenic (₃₃As) has 32 known isotopes and at least 10 isomers. Only one of these isotopes, ⁷⁵As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is ⁷³As with a half-life of 80 days.

Naturally occurring manganese (₂₅Mn) is composed of one stable isotope, ⁵⁵Mn. Twenty-seven radioisotopes have been characterized, with the most stable being ⁵³Mn with a half-life of 3.7 million years, ⁵⁴Mn with a half-life of 312.3 days, and ⁵²Mn with a half-life of 5.591 days. All of the remaining radioactive isotopes have half-lives that are less than 3 hours and the majority of these have half-lives that are less than a minute. This element also has seven meta states.

Naturally occurring scandium (₂₁Sc) is composed of one stable isotope, ⁴⁵Sc. Twenty-seven radioisotopes have been characterized, with the most stable being ⁴⁶Sc with a half-life of 83.8 days, ⁴⁷Sc with a half-life of 3.35 days, and ⁴⁸Sc with a half-life of 43.7 hours and ⁴⁴Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound ³⁹Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being ^44m2Sc.

Fermium (₁₀₀Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was ²⁵⁵Fm in 1952. ²⁵⁰Fm was independently synthesized shortly after the discovery of ²⁵⁵Fm. There are 20 known radioisotopes ranging in atomic mass from ²⁴¹Fm to ²⁶⁰Fm, and 4 nuclear isomers, ^247mFm, ^250mFm, ^251mFm, and ^253mFm. The longest-lived isotope is ²⁵⁷Fm with a half-life of 100.5 days, and the longest-lived isomer is ^247mFm with a half-life of 5.1 seconds.

Einsteinium (₉₉Es) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be discovered was ²⁵³Es in 1952. There are 18 known radioisotopes from ²⁴⁰Es to ²⁵⁷Es, and 4 nuclear isomers. The longest-lived isotope is ²⁵²Es with a half-life of 471.7 days, or around 1.293 years.

Mendelevium (₁₀₁Md) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was ²⁵⁶Md in 1955. There are 17 known radioisotopes, ranging in atomic mass from ²⁴⁴Md to ²⁶⁰Md, and 5 isomers. The longest-lived isotope is ²⁵⁸Md with a half-life of 51.3 days, and the longest-lived isomer is ^258mMd with a half-life of 57 minutes.

References

1 2 3 4 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
↑ "Standard Atomic Weights: Rhodium". CIAAW. 2017.
↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
↑ John W. Arblaster (April 2011). "The Discoverers of the Rhodium Isotopes. The thirty-eight known rhodium isotopes found between 1934 and 2010". Platinum Metals Review. 55 (2): 124–134. doi: 10.1595/147106711X555656 .
↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[5] Rh – Excited nuclear isomer.

[7] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-9] 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[10] Modes of decay:
EC: Electron capture
IT: Isomeric transition
n: Neutron emission
p: Proton emission

[11] Bold symbol as daughter – Daughter product is stable.

[12] ( ) spin value – Indicates spin with weak assignment arguments.

[order-13] 1 2 3 4 5 6 7 Order of ground state and isomer is uncertain.

[FP-14] 1 2 Fission product

[NUBASE2020-1] 1 2 3 4 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[2] "Standard Atomic Weights: Rhodium". CIAAW. 2017.

[CIAAW2021-3] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[4] John W. Arblaster (April 2011). "The Discoverers of the Rhodium Isotopes. The thirty-eight known rhodium isotopes found between 1934 and 2010". Platinum Metals Review. 55 (2): 124–134. doi: 10.1595/147106711X555656 .

[AME2020_II-6] Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.

[1]

[2]

[3]

[4]

[n 1]

[5]

[n 2]

[n 3]

[n 4]

[n 5]

[n 6]

[n 7]

[n 8]

[n 9]

EC:	Electron capture
IT:	Isomeric transition
n:	Neutron emission
p:	Proton emission