Naturally occurring rhodium (45Rh) is composed of only one stable isotope, 103Rh. The most stable radioisotopes are 101Rh with a half-life of 4.07 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 ranging from 89Rh to 122Rh - these have half-lives that are less than an hour except 100Rh (20.8 hours) and 105Rh (35.34 hours). There are also numerous meta states with the most stable being 102mRh with a half-life of 3.74 years and 101mRh with a half-life of 4.34 days.
The primary decay mode before the only stable isotope, 103Rh, is electron capture to ruthenium isotopes, and the primary mode after is beta emission to palladium isotopes. Mass numbers 102 and 104 are capable of decay in either sense.
List of isotopes
|-id=Rhodium-89 | rowspan=3|89Rh | rowspan=3 style="text-align:right" | 45 | rowspan=3 style="text-align:right" | 44 | rowspan=3|88.95099(39)# | rowspan=3 style="text-align:center" | (1995) | rowspan=3|<120 ns | β+? | 89Ru | rowspan=3|9/2+# | rowspan=3| |- | p? | 88Ru |- | β+, p? | 88Tc |-id=Rhodium-90 | rowspan=2|90Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 45 | rowspan=2|89.94457(22)# | rowspan=2 style="text-align:center" | 1994 | rowspan=2|29(3) ms | β+ | 90Ru | rowspan=2|(0+) | rowspan=2| |- | β+, p? (<0.7%) | 89Tc |-id=Rhodium-90m | rowspan=2 style="text-indent:1em" | 90mRhOrder of ground state and isomer is uncertain. | rowspan=2 colspan="3" style="text-indent:2em" | 0(500)# keV | rowspan=2 style="text-align:center" | 2001 | rowspan=2|0.56(2) s | β+ (90.4%) | 90Ru | rowspan=2|(7+) | rowspan=2| |- | β+, p (9.6%) | 89Tc |-id=Rhodium-91 | rowspan=2|91Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 46 | rowspan=2|90.93712(32)# | rowspan=2 style="text-align:center" | 1994 | rowspan=2|1.47(22) s | β+ (98.7%) | 91Ru | rowspan=2|(9/2+) | rowspan=2| |- | β+, p (1.3%) | 90Tc |-id=Rhodium-91m | rowspan=3 style="text-indent:1em" | 91mRh | rowspan=3 colspan="3" style="text-indent:2em" | 172.9(4) keV | rowspan=3 style="text-align:center" | 2005 | rowspan=3|1.8# s | β+? | 91Ru | rowspan=3|1/2−# | rowspan=3| |- | β+, p? | 90Tc |- | IT? | 91Rh |-id=Rhodium-92 | rowspan=2|92Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 47 | rowspan=2|91.9323677(47) | rowspan=2 style="text-align:center" | 1994 | rowspan=2|5.61(8) s | β+ (97.95%) | 92Ru | rowspan=2|(6+) | rowspan=2| |- | β+, p (2.05%) | 91Tc |-id=Rhodium-92m1 | rowspan=2 style="text-indent:1em" | 92m1Rh | rowspan=2 colspan="3" style="text-indent:2em" | 50(100)# keV | rowspan=2 style="text-align:center" | 2004 | rowspan=2|3.18(22) s | β+ (98.3%) | 92Ru | rowspan=2|(2+) | rowspan=2| |- | β+, p (1.7%) | 91Tc |-id=Rhodium-92m2 | style="text-indent:1em" | 92m2Rh | colspan="3" style="text-indent:2em" | 105(100)# keV | style="text-align:center" | 2017 | 232(15) ns | IT | 92Rh | (4+) | |-id=Rhodium-93 | 93Rh | style="text-align:right" | 45 | style="text-align:right" | 48 | 92.9259128(28) | style="text-align:center" | 1994 | 13.9(16) s | β+ | 93Ru | 9/2+# | |-id=Rhodium-93m | style="text-indent:1em" | 93mRh | colspan="3" style="text-indent:2em" | 267(48) keV | style="text-align:center" | 2023
| (1/2−) | |-id=Rhodium-94 | rowspan=2|94Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 49 | rowspan=2|93.9217305(36) | rowspan=2 style="text-align:center" | 1979 | rowspan=2|70.6(6) s | β+ (98.2%) | 94Ru | rowspan=2|(4+) | rowspan=2| |- | β+, p (1.8%) | 93Tc |-id=Rhodium-94m1 | style="text-indent:1em" | 94m1Rh | colspan="3" style="text-indent:2em" | 54.60(20)# keV | style="text-align:center" | 2006 | 480(30) ns | IT | 94Rh | (2+) | |-id=Rhodium-94m2 | style="text-indent:1em" | 94m2Rh | colspan="3" style="text-indent:2em" | 300(200)# keV | style="text-align:center" | 1980 | 25.8(2) s | β+ | 94Ru | (8+) | |-id=Rhodium-95 | 95Rh | style="text-align:right" | 45 | style="text-align:right" | 50 | 94.9158979(42) | style="text-align:center" | 1967 | 5.02(10) min | β+ | 95Ru | (9/2)+ | |-id=Rhodium-95m | rowspan=2 style="text-indent:1em" | 95mRh | rowspan=2 colspan="3" style="text-indent:2em" | 543.3(3) keV | rowspan=2 style="text-align:center" | 1975 | rowspan=2|1.96(4) min | IT (88%) | 95Rh | rowspan=2|(1/2)− | rowspan=2| |- | β+ (12%) | 95Ru |-id=Rhodium-96 | 96Rh | style="text-align:right" | 45 | style="text-align:right" | 51 | 95.914452(11) | style="text-align:center" | 1967 | 9.90(10) min | β+ | 96Ru | 6+ | |-id=Rhodium-96m | rowspan=2 style="text-indent:1em" | 96mRh | rowspan=2 colspan="3" style="text-indent:2em" | 51.98(9) keV | rowspan=2 style="text-align:center" | 1967 | rowspan=2|1.51(2) min | IT (60%) | 96Rh | rowspan=2|3+ | rowspan=2| |- | β+ (40%) | 96Ru |-id=Rhodium-97 | 97Rh | style="text-align:right" | 45 | style="text-align:right" | 52 | 96.911328(38) | style="text-align:center" | 1955 | 30.7(6) min | β+ | 97Ru | 9/2+ | |-id=Rhodium-97m | rowspan=2 style="text-indent:1em" | 97mRh | rowspan=2 colspan="3" style="text-indent:2em" | 258.76(18) keV | rowspan=2 style="text-align:center" | 1971 | rowspan=2|46.2(16) min | β+ (94.4%) | 97Ru | rowspan=2|1/2− | rowspan=2| |- | IT (5.6%) | 97Rh |-id=Rhodium-98 | 98Rh | style="text-align:right" | 45 | style="text-align:right" | 53 | 97.910708(13) | style="text-align:center" | 1955 | 8.72(12) min | β+ | 98Ru | (2)+ | |-id=Rhodium-98m | rowspan=2 style="text-indent:1em" | 98mRh | rowspan=2 colspan="3" style="text-indent:2em" | 56.3(10) keV | rowspan=2 style="text-align:center" | 1966 | rowspan=2|3.6(2) min | IT (89%) | 98Rh | rowspan=2|(5+) | rowspan=2| |- | β+ (11%) | 98Ru |-id=Rhodium-99 | 99Rh | style="text-align:right" | 45 | style="text-align:right" | 54 | 98.908121(21) | style="text-align:center" | 1952 | 16.1(2) d | β+ | 99Ru | 1/2− | |-id=Rhodium-99m | rowspan=2 style="text-indent:1em" | 99mRh | rowspan=2 colspan="3" style="text-indent:2em" | 64.4(5) keV | rowspan=2 style="text-align:center" | 1965 | rowspan=2|4.7(1) h | β+ | 99Ru | rowspan=2|9/2+ | rowspan=2| |- | IT? | 99Rh |-id=Rhodium-100 | rowspan=2|100Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 55 | rowspan=2|99.908114(19) | rowspan=2 style="text-align:center" | 1948 | rowspan=2|20.8(1) h | EC (95.1%) | 100Ru | rowspan=2|1− | rowspan=2| |- | β+ (4.9%) | 100Ru |-id=Rhodium-100m1 | style="text-indent:1em" | 100m1Rh | colspan="3" style="text-indent:2em" | 74.782(14) keV | style="text-align:center" | 1965 | 214.0(20) ns | IT | 100Rh | (2)+ | |-id=Rhodium-100m2 | rowspan=2 style="text-indent:1em" | 100m2Rh | rowspan=2 colspan="3" style="text-indent:2em" | 107.6(2) keV | rowspan=2 style="text-align:center" | 1974 | rowspan=2|4.6(2) min | IT (98.3%) | 100Rh | rowspan=2|(5+) | rowspan=2| |- | β+ (1.7%) | 100Ru |-id=Rhodium-100m3 | style="text-indent:1em" | 100m3Rh | colspan="3" style="text-indent:2em" | 219.61(22) keV | style="text-align:center" | 1984 | 130(10) ns | IT | 100Rh | (7+) | |-id=Rhodium-101 | 101Rh | style="text-align:right" | 45 | style="text-align:right" | 56 | 100.9061589(63) | style="text-align:center" | 1948 | 4.07(5) y | EC | 101Ru | 1/2− | |-id=Rhodium-101m | rowspan=2 style="text-indent:1em" | 101mRh | rowspan=2 colspan="3" style="text-indent:2em" | 157.32(3) keV | rowspan=2 style="text-align:center" | 1965 | rowspan=2|4.343(10) d | EC (92.80%) | 101Ru | rowspan=2|9/2+ | rowspan=2| |- | IT (7.20%) | 101Rh |-id=Rhodium-102 | rowspan=2|102Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 57 | rowspan=2|101.9068343(69) | rowspan=2 style="text-align:center" | 1941 | rowspan=2|207.0(15) d | β+ (78%) | 102Ru | rowspan=2|2− | rowspan=2| |- | β− (22%) | 102Pd |-id=Rhodium-102m | rowspan=2 style="text-indent:1em" | 102mRh | rowspan=2 colspan="3" style="text-indent:2em" | 140.73(9) keV | rowspan=2 style="text-align:center" | 1963 | rowspan=2|3.742(10) y | β+ (99.77%) | 102Ru | rowspan=2|6+ | rowspan=2| |- | IT (0.233%) | 102Rh |-id=Rhodium-103 | 103RhFission product | style="text-align:right" | 45 | style="text-align:right" | 58 | 102.9054941(25) | style="text-align:center" | 1934 | colspan=3 align=center|Stable | 1/2− | 1.0000 |-id=Rhodium-103m | style="text-indent:1em" | 103mRh | colspan="3" style="text-indent:2em" | 39.753(6) keV | style="text-align:center" | 1944 | 56.114(9) min | IT | 103Rh | 7/2+ | |-id=Rhodium-104 | rowspan=2|104Rh | rowspan=2 style="text-align:right" | 45 | rowspan=2 style="text-align:right" | 59 | rowspan=2|103.9066453(25) | rowspan=2 style="text-align:center" | 1939 | rowspan=2|42.3(4) s | β− (99.55%) | 104Pd | rowspan=2|1+ | rowspan=2| |- | β+ (0.45%) | 104Ru |-id=Rhodium-104m | rowspan=2 style="text-indent:1em" | 104mRh | rowspan=2 colspan="3" style="text-indent:2em" | 128.9679(5) keV | rowspan=2 style="text-align:center" | 1939 | rowspan=2|4.34(3) min | IT (99.87%) | 104Rh | rowspan=2|5+ | rowspan=2| |- | β− (0.13%) | 104Pd |-id=Rhodium-105 | 105Rh | style="text-align:right" | 45 | style="text-align:right" | 60 | 104.9056878(27) | style="text-align:center" | 1946 | 35.341(19) h | β− | 105Pd | 7/2+ | |-id=Rhodium-105m | style="text-indent:1em" | 105mRh | colspan="3" style="text-indent:2em" | 129.742(4) keV | style="text-align:center" | 1951 | 42.8(3) s | IT | 105Rh | 1/2− | |-id=Rhodium-106 | 106Rh | style="text-align:right" | 45 | style="text-align:right" | 61 | 105.9072859(58) | style="text-align:center" | 1946 | 30.07(35) s | β− | 106Pd | 1+ | |-id=Rhodium-106m | style="text-indent:1em" | 106mRh | colspan="3" style="text-indent:2em" | 132(11) keV | style="text-align:center" | 1955 | 131(2) min | β− | 106Pd | (6)+ | |-id=Rhodium-107 | 107Rh | style="text-align:right" | 45 | style="text-align:right" | 62 | 106.906748(13) | style="text-align:center" | 1951 | 21.7(4) min | β− | 107Pd | 7/2+ |-id=Rhodium-107m | style="text-indent:1em" | 107mRh | colspan="3" style="text-indent:2em" | 268.36(4) keV | style="text-align:center" | 1986 | >10 μs | IT | 107Rh | 1/2− | |-id=Rhodium-108 | 108Rh | style="text-align:right" | 45 | style="text-align:right" | 63 | 107.908715(15) | style="text-align:center" | 1955 | 16.8(5) s | β− | 108Pd | 1+ | |-id=Rhodium-108m | style="text-indent:1em" | 108mRh | colspan="3" style="text-indent:2em" | 115(18) keV | style="text-align:center" | 1969 | 6.0(3) min | β− | 108Pd | (5+) | |-id=Rhodium-109 | 109Rh | style="text-align:right" | 45 | style="text-align:right" | 64 | 108.9087496(43) | style="text-align:center" | 1972 | 80.8(7) s | β− | 109Pd | 7/2+ | |-id=Rhodium-109m | style="text-indent:1em" | 109mRh | colspan="3" style="text-indent:2em" | 225.873(19) keV | style="text-align:center" | 1987 | 1.66(4) μs | IT | 109Rh | 3/2+ | |-id=Rhodium-110 | 110Rh | style="text-align:right" | 45 | style="text-align:right" | 65 | 109.911080(19) | style="text-align:center" | 1963 | 3.35(12) s | β− | 110Pd | (1+) | |-id=Rhodium-110m | style="text-indent:1em" | 110mRh | colspan="3" style="text-indent:2em" | 220(150)# keV | style="text-align:center" | 1970 | 28.5(13) s | β− | 110Pd | (6+) | |-id=Rhodium-111 | 111Rh | style="text-align:right" | 45 | style="text-align:right" | 66 | 110.9116432(74) | style="text-align:center" | 1975 | 11(1) s | β− | 111Pd | (7/2+) | |-id=Rhodium-112 | 112Rh | style="text-align:right" | 45 | style="text-align:right" | 67 | 111.914405(47) | style="text-align:center" | 1971 | 3.4(4) s | β− | 112Pd | (1+) | |-id=Rhodium-112m | style="text-indent:1em" | 112mRh | colspan="3" style="text-indent:2em" | 340(70) keV | style="text-align:center" | 1988 | 6.73(15) s | β− | 112Pd | (6+) | |-id=Rhodium-113 | 113Rh | style="text-align:right" | 45 | style="text-align:right" | 68 | 112.9154402(77) | style="text-align:center" | 1971 | 2.80(12) s | β− | 113Pd | (7/2+) | |-id=Rhodium-114 | 114Rh | style="text-align:right" | 45 | style="text-align:right" | 69 | 113.918722(77) | style="text-align:center" | 1988 | 1.85(5) s | β− | 114Pd | 1+ | |-id=Rhodium-114m