Natural holmium (67Ho) contains one observationally stable isotope, 165Ho. The known isotopes of holmium range from 140Ho to 175Ho. The primary decay mode before the stable 165Ho, is beta plus decay to dysprosium isotopes, and the primary mode after is beta minus decay to erbium isotopes.
Among the synthetic radioactive isotopes the most stable is 163Ho with a half-life of 4,570 years, the next most stable is 166Ho having a half-life of 26.812 hours, and others are under 4 hours. The isomeric nuclide 166m1Ho, however, has a half-life of 1,133 years, much the longest of the meta states.
Holmium-166 (ground state) has been studied for medical application.
List of isotopes
|-id=Holmium-140 | 140Ho | style="text-align:right" | 67 | style="text-align:right" | 73 | 139.96853(54)# | style="text-align:center" | 1999 | 6(3) ms | p | 139Dy | 8+# | |-id=Holmium-141 | 141Ho | style="text-align:right" | 67 | style="text-align:right" | 74 | 140.96311(43)# | style="text-align:center" | 1998 | 4.1(1) ms | p | 140Dy | (7/2−) | |-id=Holmium-141m | style="text-indent:1em" | 141mHo | colspan="3" style="text-indent:2em" | 66(2) keV | style="text-align:center" | 1998 | 7.3(3) μs | p | 140Dy | (1/2+) | |-id=Holmium-142 | rowspan=3|142Ho | rowspan=3 style="text-align:right" | 67 | rowspan=3 style="text-align:right" | 75 | rowspan=3|141.96001(43)# | rowspan=3 style="text-align:center" | 2001 | rowspan=3|400(100) ms | β+ | 142Dy | rowspan=3|(7−, 8+) | rowspan=3| |- | β+, p (?%) | 141Tb |- | p (?%) | 141Dy |-id=Holmium-143 | 143Ho | style="text-align:right" | 67 | style="text-align:right" | 76 | 142.95486(32)# | style="text-align:center" | 2026 | 300# ms[>310 ns]
| 11/2−# | |-id=Holmium-144 | rowspan=2|144Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 77 | rowspan=2|143.9521097(91) | rowspan=2 style="text-align:center" | 1986 | rowspan=2|0.7(1) s | β+ | 144Dy | rowspan=2|(5−) | rowspan=2| |- | β+, p (?%) | 143Tb |-id=Holmium-144m | style="text-indent:1em" | 144mHo | colspan="3" style="text-indent:2em" | 265.3(3) keV | style="text-align:center" | 2001 | 519(5) ns | IT | 144Ho | (8+) | |-id=Holmium-145 | 145Ho | style="text-align:right" | 67 | style="text-align:right" | 78 | 144.9472674(80) | style="text-align:center" | 1987 | 2.4(1) s | β+ | 145Dy | (11/2−) | |-id=Holmium-146 | rowspan=2|146Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 79 | rowspan=2|145.9449935(71) | rowspan=2 style="text-align:center" | 1982 | rowspan=2|3.32(22) s | β+ | 146Dy | rowspan=2|(6−) | rowspan=2| |- | β+, p (?%) | 145Tb |-id=Holmium-147 | 147Ho | style="text-align:right" | 67 | style="text-align:right" | 80 | 146.9401423(54) | style="text-align:center" | 1982 | 5.8(4) s | β+ | 147Dy | (11/2−) | |-id=Holmium-147m | style="text-indent:1em" | 147mHo | colspan="3" style="text-indent:2em" | 2687.1(4) keV | style="text-align:center" | 1982 | 315(30) ns | IT | 147Ho | (27/2−) | |-id=Holmium-148 | 148Ho | style="text-align:right" | 67 | style="text-align:right" | 81 | 147.937744(90) | style="text-align:center" | 1979 | 2.2(11) s | β+ | 148Dy | (1+) | |-id=Holmium-148m1 | rowspan=2 style="text-indent:1em" | 148m1Ho | rowspan=2 colspan="3" style="text-indent:2em" | 250(100)# keV | rowspan=2 style="text-align:center" | 1982 | rowspan=2|9.49(12) s | β+ (99.92%) | 148Dy | rowspan=2|(5−) | rowspan=2| |- | β+, p (0.08%) | 147Tb |-id=Holmium-148m2 | style="text-indent:1em" | 148m2Ho | colspan="3" style="text-indent:2em" | 940(100)# keV | style="text-align:center" | 1984 | 2.36(6) ms | IT | 148m1Ho | (10)+ | |-id=Holmium-149 | 149Ho | style="text-align:right" | 67 | style="text-align:right" | 82 | 148.933820(13) | style="text-align:center" | 1979 | 21.1(2) s | β+ | 149Dy | (11/2−) | |-id=Holmium-149m | style="text-indent:1em" | 149mHo | colspan="3" style="text-indent:2em" | 48.80(20) keV | style="text-align:center" | 1989 | 56(3) s | β+ | 149Dy | (1/2+) | |-id=Holmium-150 | 150Ho | style="text-align:right" | 67 | style="text-align:right" | 83 | 149.933498(15) | style="text-align:center" | 1963 | 76.8(18) s | β+ | 150Dy | (2)− | |-id=Holmium-150m1 | style="text-indent:1em" | 150m1HoOrder of ground state and isomer is uncertain. | colspan="3" style="text-indent:2em" | 0(50) keV | style="text-align:center" | 1980 | 23.3(3) s | β+ | 150Dy | (9)+ | |-id=Holmium-150m2 | style="text-indent:1em" | 150m2Ho | colspan="3" style="text-indent:2em" | 7900(50) keV | style="text-align:center" | 1981 | 787(36) ns | IT | 150Ho | (28−) | |-id=Holmium-151 | rowspan=2|151Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 84 | rowspan=2|150.9316982(89) | rowspan=2 style="text-align:center" | 1963 | rowspan=2|35.2(1) s | β+ (78%) | 151Dy | rowspan=2|11/2− | rowspan=2| |- | α (22%) | 147Tb |-id=Holmium-151m | rowspan=2 style="text-indent:1em" | 151mHo | rowspan=2 colspan="3" style="text-indent:2em" | 41.0(2) keV | rowspan=2 style="text-align:center" | 1963 | rowspan=2|47.2(13) s | α (77%) | 147Tb | rowspan=2|1/2+ | rowspan=2| |- | β+ (23%) | 151Dy |-id=Holmium-152 | rowspan=2|152Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 85 | rowspan=2|151.931718(13) | rowspan=2 style="text-align:center" | 1963 | rowspan=2|161.8(3) s | β+ (88%) | 152Dy | rowspan=2|2− | rowspan=2| |- | α (12%) | 148Tb |-id=Holmium-152m1 | rowspan=2 style="text-indent:1em" | 152m1Ho | rowspan=2 colspan="3" style="text-indent:2em" | 160(3) keV | rowspan=2 style="text-align:center" | 1963 | rowspan=2|49.8(2) s | β+ (89.2%) | 152Dy | rowspan=2|9+ | rowspan=2| |- | α (10.8%) | 148Tb
|-id=Holmium-152m2 | style="text-indent:1em" | 152m2Ho | colspan="3" style="text-indent:2em" | 3019.59(19) keV | style="text-align:center" | 1994 | 8.4(3) μs | IT | 152Ho | 19− | |-id=Holmium-153 | rowspan=2|153Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 86 | rowspan=2|152.9302067(54) | rowspan=2 style="text-align:center" | 1963 | rowspan=2|2.01(3) min | β+ (99.95%) | 153Dy | rowspan=2|11/2− | rowspan=2| |- | α (0.051%) | 149Tb |-id=Holmium-153m1 | rowspan=2 style="text-indent:1em" | 153m1Ho | rowspan=2 colspan="3" style="text-indent:2em" | 68.7(3) keV | rowspan=2 style="text-align:center" | 1971 | rowspan=2|9.3(5) min | β+ (99.82%) | 153Dy | rowspan=2|1/2+ | rowspan=2| |- | α (0.18%) | 149Tb |-id=Holmium-153m2 | style="text-indent:1em" | 153m2Ho | colspan="3" style="text-indent:2em" | 2772.3(14) keV | style="text-align:center" | 1980 | 229(2) ns | IT | 153Ho | 31/2+ | |-id=Holmium-154 | rowspan=2|154Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 87 | rowspan=2|153.9306068(88) | rowspan=2 style="text-align:center" | 1966 | rowspan=2|11.76(19) min | β+ (99.98%) | 154Dy | rowspan=2|2− | rowspan=2| |- | α (0.019%) | 150Tb |-id=Holmium-154m | rowspan=3 style="text-indent:1em" | 154mHo | rowspan=3 colspan="3" style="text-indent:2em" | 243(28) keV | rowspan=3 style="text-align:center" | 1968 | rowspan=3|3.10(14) min | β+ | 154Dy | rowspan=3|8+ | rowspan=3| |- | α (<0.001%) | 150Tb |- | IT (rare) | 154Ho |-id=Holmium-155 | 155Ho | style="text-align:right" | 67 | style="text-align:right" | 88 | 154.929103(19) | style="text-align:center" | 1959 | 48(2) min | β+ | 155Dy | 5/2+ | |-id=Holmium-155m | style="text-indent:1em" | 155mHo | colspan="3" style="text-indent:2em" | 141.87(11) keV | style="text-align:center" | 1979 | 880(80) μs | IT | 155Ho | 11/2− | |-id=Holmium-156 | 156Ho | style="text-align:right" | 67 | style="text-align:right" | 89 | 155.929642(41) | style="text-align:center" | 1957 | 56(1) min | β+ | 156Dy | 4− | |-id=Holmium-156m1 | style="text-indent:1em" | 156m1Ho | colspan="3" style="text-indent:2em" | 52.37(30) keV | style="text-align:center" | (1995)Only published in a conference proceeding and not a refereed journal. | 9.5(15) s | IT | 156Ho | 1− | |-id=Holmium-156m2 | rowspan=2 style="text-indent:1em" | 156m2Ho | rowspan=2 colspan="3" style="text-indent:2em" | 230(50) keV |rowspan=2 style="text-align:center" | (1999) | rowspan=2|7.6(3) min | β+ (75%) | 156Dy | rowspan=2|9+ | rowspan=2| |- | IT (25%) | 156Ho |-id=Holmium-157 | 157Ho | style="text-align:right" | 67 | style="text-align:right" | 90 | 156.928252(25) | style="text-align:center" | 1965 | 12.6(2) min | β+ | 157Dy | 7/2− | |-id=Holmium-158 | 158Ho | style="text-align:right" | 67 | style="text-align:right" | 91 | 157.928945(29) | style="text-align:center" | 1960 | 11.3(4) min | β+ | 158Dy | 5+ | |-id=Holmium-158m1 | rowspan=2 style="text-indent:1em" | 158m1Ho | rowspan=2 colspan="3" style="text-indent:2em" | 67.20(1) keV | rowspan=2 style="text-align:center" | 1962 | rowspan=2|28(2) min | IT (91%) | 158Ho | rowspan=2|2− | rowspan=2| |- | β+ (9%) | 158Dy |-id=Holmium-158m2 | style="text-indent:1em" | 158m2Ho | colspan="3" style="text-indent:2em" | 91.595(12) keV | style="text-align:center" | (2005) | 140(25) ns | IT | 158Ho | (2−) | |-id=Holmium-158m3 | style="text-indent:1em" | 158m3Ho | colspan="3" style="text-indent:2em" | 180(70)# keV | style="text-align:center" | 1974 | 21.3(23) min | β+ | 158Dy | (9+) | |-id=Holmium-159 | 159Ho | style="text-align:right" | 67 | style="text-align:right" | 92 | 158.9277187(33) | style="text-align:center" | 1958 | 33.05(11) min | β+ | 159Dy | 7/2− | |-id=Holmium-159m | style="text-indent:1em" | 159mHo | colspan="3" style="text-indent:2em" | 205.91(5) keV | style="text-align:center" | 1965 | 8.30(8) s | IT | 159Ho | 1/2+ | |-id=Holmium-160 | 160Ho | style="text-align:right" | 67 | style="text-align:right" | 93 | 159.928736(16) | style="text-align:center" | 1950 | 25.6(3) min | β+ | 160Dy | 5+ | |-id=Holmium-160m1 | rowspan=2 style="text-indent:1em" | 160m1Ho | rowspan=2 colspan="3" style="text-indent:2em" | 59.98(3) keV | rowspan=2 style="text-align:center" | 1955 | rowspan=2|5.02(5) h | IT (73%) | 160Ho | rowspan=2|2− | rowspan=2| |- | β+ (27%) | 160Dy |-id=Holmium-160m2 | style="text-indent:1em" | 160m2Ho | colspan="3" style="text-indent:2em" | 197(16) keV | style="text-align:center" | 1988 | ~3 s | IT | 160Ho | (9+) | |-id=Holmium-161 | 161Ho | style="text-align:right" | 67 | style="text-align:right" | 94 | 160.9278618(23) | style="text-align:center" | 1954 | 2.48(5) h | EC | 161Dy | 7/2− | |-id=Holmium-161m | style="text-indent:1em" | 161mHo | colspan="3" style="text-indent:2em" | 211.15(3) keV | style="text-align:center" | 1965 | 6.76(7) s | IT | 161Ho | 1/2+ | |-id=Holmium-162 | 162Ho | style="text-align:right" | 67 | style="text-align:right" | 95 | 161.9291025(33) | style="text-align:center" | 1957 | 15.0(10) min | β+ | 162Dy | 1+ | |-id=Holmium-162m | rowspan=2 style="text-indent:1em" | 162mHo | rowspan=2 colspan="3" style="text-indent:2em" | 105.87(6) keV | rowspan=2 style="text-align:center" | 1961 | rowspan=2|67.0(7) min | IT (62%) | 162Ho | rowspan=2|6− | rowspan=2| |- | β+ (38%) | 162Dy |-id=Holmium-163 | 163Ho | style="text-align:right" | 67 | style="text-align:right" | 96 | 162.92874026(74) | style="text-align:center" | 1957 | 4570(25) y | EC | 163Dy | 7/2− | |-id=Holmium-163m1 | style="text-indent:1em" | 163m1Ho | colspan="3" style="text-indent:2em" | 297.88(7) keV | style="text-align:center" | 1957 | 1.09(3) s | IT | 163Ho | 1/2+ | |-id=Holmium-163m2 | style="text-indent:1em" | 163m2Ho | colspan="3" style="text-indent:2em" | 2109.4(4) keV | style="text-align:center" | 2012 | 800(150) ns | IT | 163Ho | (23/2+) | |-id=Holmium-164 | rowspan=2|164Ho | rowspan=2 style="text-align:right" | 67 | rowspan=2 style="text-align:right" | 97 | rowspan=2|163.9302405(15) | rowspan=2 style="text-align:center" | 1938 | rowspan=2|28.8(5) min | EC (61%) | 164Dy | rowspan=2|1+ | rowspan=2| |- | β− (39%) | 164Er |-id=Holmium-164m | style="text-indent:1em" | 164mHo | colspan="3" style="text-indent:2em" | 139.78(7) keV | style="text-align:center" | 1966 | 36.6(3) min | IT | 164Ho | 6− | |-id=Holmium-165 | 165Ho | style="text-align:right" | 67 | style="text-align:right" | 98 | 164.93032912(84)