Naturally occurring rhodium (45 Rh) is composed of only one stable isotope , 103 Rh.[ 4] The most stable radioisotopes are 101 Rh with a half-life of 3.3 years, 102 Rh with a half-life of 207 days, and 99 Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (89 Rh) to 121.943 u (122 Rh). Most of these have half-lives that are less than an hour except 100 Rh (half-life: 20.8 hours) and 105 Rh (half-life: 35.36 hours). There are also numerous meta states with the most stable being 102m Rh (0.141 MeV) with a half-life of about 3.7 years and 101m Rh (0.157 MeV) with a half-life of 4.34 days.
The primary decay mode before the only stable isotope, 103 Rh, is electron capture and the primary mode after is beta emission . The primary decay product before 103 Rh 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 andparity [ 1] [ n 7] [ n 4]
Isotopic abundance
Excitation energy[ n 4]
90 Rh
45
45
89.94457(22)#
29(3) ms
β+
90 Ru
(0+)
β+ , p ? (<0.7%)
89 Tc
90m Rh[ n 8]
0(500)# keV
0.56(2) s
β+ (90.4%)
90 Ru
(7+)
β+ , p (9.6%)
89 Tc
91 Rh
45
46
90.93712(32)#
1.47(22) s
β+ (98.7%)
91 Ru
(9/2+)
β+ , p (1.3%)
90 Tc
91m Rh
172.9(4) keV
1.8# s
β+ ?
91 Ru
1/2−#
β+ , p?
90 Tc
IT ?
91 Rh
92 Rh
45
47
91.9323677(47)
5.61(8) s
β+ (97.95%)
92 Ru
(6+)
β+ , p (2.05%)
91 Tc
92m1 Rh
50(100)# keV
3.18(22) s
β+ (98.3%)
92 Ru
(2+)
β+ , p (1.7%)
91 Tc
92m2 Rh
105(100)# keV
232(15) ns
IT
92 Rh
(4+)
93 Rh
45
48
92.9259128(28)
13.9(16) s
β+
93 Ru
9/2+#
94 Rh
45
49
93.9217305(36)
70.6(6) s
β+ (98.2%)
94 Ru
(4+)
β+ , p (1.8%)
93 Tc
94m1 Rh
54.60(20)# keV
480(30) ns
IT
94 Rh
(2+)
94m2 Rh[ n 8]
300(200)# keV
25.8(2) s
β+
94 Ru
(8+)
95 Rh
45
50
94.9158979(42)
5.02(10) min
β+
95 Ru
(9/2)+
95m Rh
543.3(3) keV
1.96(4) min
IT (88%)
95 Rh
(1/2)−
β+ (12%)
95 Ru
96 Rh
45
51
95 914452(11)
9.90(10) min
β+
96 Ru
6+
96m Rh
51.98(9) keV
1.51(2) min
IT (60%)
96 Rh
3+
β+ (40%)
96 Ru
97 Rh
45
52
96.911328(38)
30.7(6) min
β+
97 Ru
9/2+
97m Rh
258.76(18) keV
46.2(16) min
β+ (94.4%)
97 Ru
1/2−
IT (5.6%)
97 Rh
98 Rh
45
53
97.910708(13)
8.72(12) min
β+
98 Ru
(2)+
98m Rh[ n 8]
56.3(10) keV
3.6(2) min
IT (89%)
98 Rh
(5+)
β+ (11%)
98 Ru
99 Rh
45
54
98.908121(21)
16.1(2) d
β+
99 Ru
1/2−
99m Rh
64.4(5) keV
4.7(1) h
β+
99 Ru
9/2+
IT?
99 Rh
100 Rh
45
55
99.908114(19)
20.8(1) h
EC (95.1%)
100 Ru
1−
β+ (4.9%)
100 Ru
100m1 Rh
74.782(14) keV
214.0(20) ns
IT
100 Rh
(2)+
100m2 Rh
107.6(2) keV
4.6(2) min
IT (98.3%)
100 Rh
(5+)
β+ (1.7%)
100 Ru
100m3 Rh
219.61(22) keV
130(10) ns
IT
100 Rh
(7+)
101 Rh
45
56
100.9061589(63)
4.07(5) y
EC
101 Ru
1/2−
101m Rh
157.32(3) keV
4.343(10) d
EC (92.80%)
101 Ru
9/2+
IT (7.20%)
101 Rh
102 Rh
45
57
101.9068343(69)
207.0(15) d
β+ (78%)
102 Ru
2−
β− (22%)
102 Pd
102m Rh
140.73(9) keV
3.742(10) y
β+ (99.77%)
102 Ru
6+
IT (0.233%)
102 Rh
103 Rh[ n 9]
45
58
102.9054941(25)
Stable
1/2−
1.0000
103m Rh
39.753(6) keV
56.114(9) min
IT
103 Rh
7/2+
104 Rh
45
59
103.9066453(25)
42.3(4) s
β− (99.55%)
104 Pd
1+
β+ (0.45%)
104 Ru
104m Rh
128.9679(5) keV
4.34(3) min
IT (99.87%)
104 Rh
5+
β− (0.13%)
104 Pd
105 Rh[ n 9]
45
60
104.9056878(27)
35.341(19) h
β−
105 Pd
7/2+
105m Rh
129.742(4) keV
42.8(3) s
IT
105 Rh
1/2−
106 Rh
45
61
105.9072859(58)
30.07(35) s
β−
106 Pd
1+
106m Rh
132(11) keV
131(2) min
β−
106 Pd
(6)+
107 Rh
45
62
106.906748(13)
21.7(4) min
β−
107 Pd
7/2+
107m Rh
268.36(4) keV
>10 μs
IT
107 Rh
1/2−
108 Rh
45
63
107.908715(15)
16.8(5) s
β−
108 Pd
1+
108m Rh
115(18) keV
6.0(3) min
β−
108 Pd
(5+)
109 Rh
45
64
108.9087496(43)
80.8(7) s
β−
109 Pd
7/2+
109m Rh
225.873(19) keV
1.66(4) μs
IT
109 Pd
3/2+
110 Rh
45
65
109.911080(19)
3.35(12) s
β−
110 Pd
(1+)
110m Rh[ n 8]
220(150)# keV
28.5(13) s
β−
110 Pd
(6+)
111 Rh
45
66
110.9116432(74)
11(1) s
β−
111 Pd
(7/2+)
112 Rh
45
67
111.914405(47)
3.4(4) s
β−
112 Pd
(1+)
112m Rh
340(70) keV
6.73(15) s
β−
112 Pd
(6+)
113 Rh
45
68
112.9154402(77)
2.80(12) s
β−
113 Pd
(7/2+)
114 Rh
45
69
113.918722(77)
1.85(5) s
β−
114 Pd
1+
114m Rh[ n 8]
200(150)# keV
1.85(5) s
β−
114 Pd
(7−)
115 Rh
45
70
114.9203116(79)
1.03(3) s
β−
115 Pd
(7/2+)
β− , n?
114 Pd
116 Rh
45
71
115.924062(79)
685(39) ms
β− (>97.9%)
116 Pd
1+
β− , n? (<2.1%)
115 Pd
116m Rh[ n 8]
200(150)# keV
570(50) ms
β− (>97.9%)
116 Pd
(6−)
β− , n? (<2.1%)
115 Pd
117 Rh
45
72
116.9260363(95)
421(30) ms
β−
117 Pd
7/2+#
β− , n? (<7.6%)
115 Pd
117m Rh
321.2(10) keV
138(17) ns
IT
117 Rh
3/2+#
118 Rh
45
73
117.930341(26)
282(9) ms
β− (96.9%)
118 Pd
1+#
β− , n (3.1%)
117 Pd
118m Rh[ n 8]
200(150)# keV
310(30) ms
β− (96.9%)
118 Pd
6−#
β− , n (3.1%)
117 Pd
IT?
118 Rh
119 Rh
45
74
118.932557(10)
190(6) ms
β− (93.6%)
119 Pd
7/2+#
β− , n (6.4%)
118 Pd
120 Rh
45
75
119.93707(22)#
129.6(42) ms
β−
120 Pd
8−#
β− , n (<9.3%)
119 Pd
β− , 2n?
118 Pd
120m Rh
157.2(7) keV
295(16) ns
IT
120 Rh
6#
121 Rh
45
76
120.93961(67)
74(4) ms
β−
121 Pd
7/2+#
β− , n (>11%)
120 Pd
122 Rh
45
77
121.94431(32)#
51(6) ms
β−
122 Pd
7−#
β− , n (<3.9%)
121 Pd
β− , 2n?
120 Pd
122m Rh
271.0(7) keV
830(120) ns
IT
122 Rh
4+#
123 Rh
45
78
122.94719(43)#
42(4) ms
β−
123 Pd
7/2+#
β− , n (>24%)
122 Pd
β− , 2n?
121 Pd
124 Rh
45
79
123.95200(43)#
30(2) ms
β−
124 Pd
2+#
β− , n (<31%)
123 Pd
β− , 2n?
122 Pd
125 Rh
45
80
124.95509(54)#
26.5(20) ms
β−
125 Pd
7/2+#
β− , n?
124 Pd
β− , 2n?
123 Pd
126 Rh
45
81
125.96006(54)#
19(3) ms
β−
126 Pd
1−#
β− , n?
125 Pd
β− , 2n?
124 Pd
127 Rh
45
82
126.96379(64)#
28(14) ms
β−
127 Pd
7/2+#
β− , n?
126 Pd
β− , 2n?
125 Pd
128 Rh
45
83
127.97065(32)#
8# ms [>550 ns]
β− ?
128 Pd
β− , n?
127 Pd
β− , 2n?
126 Pd
This table header & footer:
^ m Rh – 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).
^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^
Modes of decay:
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ a b c d e f g Order of ground state and isomer is uncertain.
^ a b Fission product
References
^ a b c d 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:
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 .
Group
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Period
Hydrogen and alkali metals
Alkaline earth metals
Pnictogens
Chalcogens
Halogens
Noble gases
①
1
2
②
3
4
5
6
7
8
9
10
③
11
12
13
14
15
16
17
18
④
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
⑤
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
⑥
55
56
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
⑦
87
88
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
⑧
119
120
57
58
59
60
61
62
63
64
65
66
67
68
69
70
89
90
91
92
93
94
95
96
97
98
99
100
101
102
Information related to Isotopes of rhodium