Isotopes of rhodium

Naturally occurring rhodium (₄₅Rh) is composed of only one stable isotope, ¹⁰³Rh.[2] 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-lifes 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.

Main isotopes of rhodium (₄₅Rh)

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct ^99Rh syn 16.1 d ε ^99Ru γ – ^101mRh syn 4.34 d ε ^101Ru IT ^101Rh γ – ^101Rh syn 3.3 y ε ^101Ru γ – ^102mRh syn 3.7 y ε ^102Ru γ – ^102Rh syn 207 d ε ^102Ru β^+ ^102Ru β^− ^102Pd γ – ^103Rh 100% stable ^105Rh syn 35.36 h β^− ^105Pd γ –
Standard atomic weight Ar, standard(Rh)	102.90550(2)[1]

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) [n 2][n 3]	Half-life [n 4]	Decay mode [n 5]	Daughter isotope [n 6]	Spin and parity [n 7][n 4]	Natural abundance (mole fraction)
	Excitation energy[n 4]							Normal proportion	Range of variation
^89Rh	45	44	88.94884(48)#	10# ms [>1.5 μs]	β^+	^89Ru	7/2+#
^90Rh	45	45	89.94287(54)#	15(7) ms [12(+9−4) ms]	β^+	^90Ru	0+#
^90mRh	0(500)# keV			1.1(3) s [1.0(+3−2) s]			9+#
^91Rh	45	46	90.93655(43)#	1.74(14) s	β^+	^91Ru	7/2+#
^91mRh				1.46(11) s			(1/2−)
^92Rh	45	47	91.93198(43)#	4.3(13) s	β^+	^92Ru	(6+)
^92mRh				4.66(25) s [2.9(+15−8) s]			(≥6+)
^93Rh	45	48	92.92574(43)#	11.9(7) s	β^+	^93Ru	9/2+#
^94Rh	45	49	93.92170(48)#	70.6(6) s	β^+ (98.2%)	^94Ru	(2+, 4+)
					β^+, p (1.79%)	^93Tc
^94mRh	300(200)# keV			25.8(2) s	β^+	^94Ru	(8+)
^95Rh	45	50	94.91590(16)	5.02(10) min	β^+	^95Ru	(9/2)+
^95mRh	543.3(3) keV			1.96(4) min	IT (88%)	^95Rh	(1/2)−
					β^+ (12%)	^95Ru
^96Rh	45	51	95.914461(14)	9.90(10) min	β^+	^96Ru	(6+)
^96mRh	52.0(1) keV			1.51(2) min	IT (60%)	^96Rh	(3+)
					β^+ (40%)	^96Ru
^97Rh	45	52	96.91134(4)	30.7(6) min	β^+	^97Ru	9/2+
^97mRh	258.85(17) keV			46.2(16) min	β^+ (94.4%)	^97Ru	1/2−
					IT (5.6%)	^97Rh
^98Rh	45	53	97.910708(13)	8.72(12) min	β^+	^98Ru	(2)+
^98mRh	60(50)# keV			3.6(2) min	IT	^98Rh	(5+)
					β^+	^98Ru
^99Rh	45	54	98.908132(8)	16.1(2) d	β^+	^99Ru	1/2−
^99mRh	64.3(4) keV			4.7(1) h	β^+ (99.83%)	^99Ru	9/2+
					IT (.16%)	^99Rh
^100Rh	45	55	99.908122(20)	20.8(1) h	β^+	^100Ru	1−
^100m1Rh	107.6(2) keV			4.6(2) min	IT (98.3%)	^100Rh	(5+)
					β^+ (1.7%)	^100Ru
^100m2Rh	74.78(2) keV			214.0(20) ns			(2)+
^100m3Rh	112.0+X keV			130(10) ns			(7+)
^101Rh	45	56	100.906164(18)	3.3(3) y	EC	^101Ru	1/2−
^101mRh	157.32(4) keV			4.34(1) d	EC (93.6%)	^101Ru	9/2+
					IT (6.4%)	^101Rh
^102Rh	45	57	101.906843(5)	207.0(15) d	β^+ (80%)	^102Ru	(1−, 2−)
					β^− (20%)	^102Pd
^102mRh	140.75(8) keV			3.742(10) y	β^+ (99.77%)	^102Ru	6+
					IT (.23%)	^102Rh
^103Rh[n 8]	45	58	102.905504(3)	Stable			1/2−	1.0000
^103mRh	39.756(6) keV			56.114(9) min	IT	^103Rh	7/2+
^104Rh	45	59	103.906656(3)	42.3(4) s	β^− (99.55%)	^104Pd	1+
					β^+ (.449%)	^104Ru
^104mRh	128.967(4) keV			4.34(3) min			5+
^105Rh[n 8]	45	60	104.905694(4)	35.36(6) h	β^−	^105Pd	7/2+
^105mRh	129.781(4) keV			42.9(3) s	IT	^105Rh	1/2−
					β^−	^105Pd
^106Rh	45	61	105.907287(8)	29.80(8) s	β^−	^106Pd	1+
^106mRh	136(12) 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			1/2−
^108Rh	45	63	107.90873(11)	16.8(5) s	β^−	^108Pd	1+
^108mRh	-60(110) keV			6.0(3) min	β^−	^108Pd	(5)(+#)
^109Rh	45	64	108.908737(13)	80(2) s	β^−	^109Pd	7/2+
^110Rh	45	65	109.91114(5)	28.5(15) s	β^−	^110Pd	(>3)(+#)
^110mRh	-60(50) keV			3.2(2) s	β^−	^110Pd	1+
^111Rh	45	66	110.91159(3)	11(1) s	β^−	^111Pd	(7/2+)
^112Rh	45	67	111.91439(6)	3.45(37) s	β^−	^112Pd	1+
^112mRh	330(70) keV			6.73(15) s	β^−	^112Pd	(4, 5, 6)
^113Rh	45	68	112.91553(5)	2.80(12) s	β^−	^113Pd	(7/2+)
^114Rh	45	69	113.91881(12)	1.85(5) s	β^− (>99.9%)	^114Pd	1+
					β^−, n (<.1%)	^113Pd
^114mRh	200(150)# keV			1.85(5) s	β^−	^114Pd	(4, 5)
^115Rh	45	70	114.92033(9)	0.99(5) s	β^−	^115Pd	(7/2+)#
^116Rh	45	71	115.92406(15)	0.68(6) s	β^− (>99.9%)	^116Pd	1+
					β^−, n (<.1%)	^115Pd
^116mRh	200(150)# keV			570(50) ms	β^−	^116Pd	(6−)
^117Rh	45	72	116.92598(54)#	0.44(4) s	β^−	^117Pd	(7/2+)#
^118Rh	45	73	117.93007(54)#	310(30) ms	β^−	^118Pd	(4−10)(+#)
^119Rh	45	74	118.93211(64)#	300# ms [>300 ns]	β^−	^119Pd	7/2+#
^120Rh	45	75	119.93641(64)#	200# ms [>300 ns]	β^−	^120Pd
^121Rh	45	76	120.93872(97)#	100# ms [>300 ns]	β^−	^121Pd	7/2+#
^122Rh	45	77	121.94321(75)#	50# ms [>300 ns]

1. ^mRh – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:

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

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. Fission product

References

1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
2. 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.

• 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
• Isotopic compositions and standard atomic masses from:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
• 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.