Isotopes of rhodium

Naturally occurring rhodium (Rh) is composed of only one stable isotope, ¹⁰³Rh.^[1] 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.

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.
Relative atomic mass: 102.90550(2).

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)[2][n 1]	daughter isotope(s)[n 2]	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
^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%)	Rh
^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 3]	45	58	102.905504(3)	Stable[n 4]			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 3]	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. Abbreviations:
   EC: Electron capture
   IT: Isomeric transition
2. Bold for stable isotopes
3. Fission product
4. Theoretically capable of spontaneous fission

Notes

• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.

References

1. 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.
2. "Universal Nuclide Chart". nucleonica. (registration required (help)).

• Isotope masses from:
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). 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:
  • J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
  • M. E. Wieser (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. See editing notes on this article's talk page.
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.