Element: Holmium
General data
| Element name | Holmium |
|---|---|
| Chemical symbol | Ho |
| Atomic number Z | 67 |
| Year discovered | 1878 |
| Standard state (25°C) | Solid |
| Category | Lanthanide |
| Block | f |
| Atomic mass | 164.93 |
| CPK color | #00FF9C |
Physical properties
| Melting point | 1747 K (1474 °C) |
|---|---|
| Boiling point | 2973 K (2700 °C) |
| Density | 8.8 g/cm³ |
Energy properties
| First ionization energy | 6.022 eV |
|---|---|
| Electron affinity | no data |
Atomic structure
| Protons | 67 (Atomic number) |
|---|---|
| Neutrons (Ho-165, most abundant isotope) | 98 |
| Electrons | 67 |
| Electron configuration | [Xe] 6s² 4f¹¹ |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.23 |
| Atomic radius (van der Waals) | 216 pm |
Ionization energies - NIST ASD (67 states)
| State | Charge | Ioniz. energy (eV) | Type |
|---|---|---|---|
| Ho I | 0+ | 6.0215 ± 0.0006 | measured |
| Ho II | 1+ | 11.781 ± 0.02 | semi-empirical |
| Ho III | 2+ | 22.79 ± 0.03 | semi-empirical |
| Ho IV | 3+ | 42.52 ± 0.08 | semi-empirical |
| Ho V | 4+ | 63.9 ± 0.3 | semi-empirical |
| Ho VI | 5+ | 95 ± 5 | calculated |
| Ho VII | 6+ | 112 ± 6 | calculated |
| Ho VIII | 7+ | 129 ± 6 | calculated |
| Ho IX | 8+ | 155 ± 8 | calculated |
| Ho X | 9+ | 173 ± 9 | calculated |
| Ho XI | 10+ | 197 ± 10 | calculated |
| Ho XII | 11+ | 229 ± 12 | calculated |
| Ho XIII | 12+ | 263 ± 14 | calculated |
| Ho XIV | 13+ | 284 ± 14 | calculated |
| Ho XV | 14+ | 305 ± 15 | calculated |
| Ho XVI | 15+ | 340 ± 17 | calculated |
| Ho XVII | 16+ | 373 ± 19 | calculated |
| Ho XVIII | 17+ | 408 ± 20 | calculated |
| Ho XIX | 18+ | 441 ± 22 | calculated |
| Ho XX | 19+ | 475 ± 24 | calculated |
| Ho XXI | 20+ | 510 ± 4 | calculated |
| Ho XXII | 21+ | 715 ± 4 | calculated |
| Ho XXIII | 22+ | 755 ± 4 | calculated |
| Ho XXIV | 23+ | 797 ± 4 | calculated |
| Ho XXV | 24+ | 842 ± 4 | calculated |
| Ho XXVI | 25+ | 885 ± 4 | calculated |
| Ho XXVII | 26+ | 929 ± 4 | calculated |
| Ho XXVIII | 27+ | 985 ± 4 | calculated |
| Ho XXIX | 28+ | 1029 ± 4 | calculated |
| Ho XXX | 29+ | 1077 ± 4 | calculated |
| Ho XXXI | 30+ | 1122 ± 4 | calculated |
| Ho XXXII | 31+ | 1300 ± 4 | calculated |
| Ho XXXIII | 32+ | 1346 ± 4 | calculated |
| Ho XXXIV | 33+ | 1395 ± 5 | calculated |
| Ho XXXV | 34+ | 1443 ± 5 | calculated |
| Ho XXXVI | 35+ | 1545 ± 5 | calculated |
| Ho XXXVII | 36+ | 1598 ± 5 | calculated |
| Ho XXXVIII | 37+ | 1719 ± 4 | calculated |
| Ho XXXIX | 38+ | 1773.6 ± 0.9 | semi-empirical |
| Ho XL | 39+ | 3018 ± 4 | calculated |
| Ho XLI | 40+ | 3125 ± 4 | calculated |
| Ho XLII | 41+ | 3238 ± 4 | calculated |
| Ho XLIII | 42+ | 3359 ± 4 | calculated |
| Ho XLIV | 43+ | 3476 ± 4 | calculated |
| Ho XLV | 44+ | 3592 ± 4 | calculated |
| Ho XLVI | 45+ | 3760 ± 4 | calculated |
| Ho XLVII | 46+ | 3880 ± 4 | calculated |
| Ho XLVIII | 47+ | 4009 ± 4 | calculated |
| Ho XLIX | 48+ | 4131 ± 4 | calculated |
| Ho L | 49+ | 4469 ± 4 | calculated |
| Ho LI | 50+ | 4576 ± 4 | calculated |
| Ho LII | 51+ | 4693 ± 4 | calculated |
| Ho LIII | 52+ | 4802 ± 4 | calculated |
| Ho LIV | 53+ | 5135 ± 5 | calculated |
| Ho LV | 54+ | 5258 ± 5 | calculated |
| Ho LVI | 55+ | 5494 ± 5 | calculated |
| Ho LVII | 56+ | 5611 ± 5 | calculated |
| Ho LVIII | 57+ | 12495 ± 6 | calculated |
| Ho LIX | 58+ | 12790 ± 6 | calculated |
| Ho LX | 59+ | 13116 ± 7 | calculated |
| Ho LXI | 60+ | 13417 ± 10 | calculated |
| Ho LXII | 61+ | 14639 ± 12 | calculated |
| Ho LXIII | 62+ | 14998 ± 15 | calculated |
| Ho LXIV | 63+ | 15448 ± 19 | calculated |
| Ho LXV | 64+ | 15745.77 ± 0.11 | calculated |
| Ho LXVI | 65+ | 63772.42 ± 0.11 | calculated |
| Ho LXVII | 66+ | 65137.13 ± 0.16 | calculated |
Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.
Photos
Isotopes (39)
| A | N | Half-life | Decay |
|---|---|---|---|
| Ho-140 | 73 | 6 ms | p |
| Ho-141 | 74 | 4.1 ms | p |
| Ho-142 | 75 | 0.4 s | EC/β⁺ |
| Ho-143 | 76 | unknown | EC/β⁺ |
| Ho-144 | 77 | 0.7 s | EC/β⁺ |
| Ho-145 | 78 | 2.4 s | EC/β⁺ |
| Ho-146 | 79 | 3.3 s | EC/β⁺ |
| Ho-147 | 80 | 5.8 s | EC/β⁺ |
| Ho-148 | 81 | 2.2 s | EC/β⁺ |
| Ho-149 | 82 | 21.0 s | EC/β⁺ |
| Ho-150 | 83 | 77 s | EC/β⁺ |
| Ho-151 | 84 | 35.2 s | EC/β⁺ |
| Ho-152 | 85 | 147 s | EC/β⁺ |
| Ho-153 | 86 | 2.01 min | EC/β⁺ |
| Ho-154 | 87 | 11.76 min | EC/β⁺ |
| Ho-155 | 88 | 48 min | EC/β⁺ |
| Ho-156 | 89 | 56 min | EC/β⁺ |
| Ho-157 | 90 | 12.7 min | EC/β⁺ |
| Ho-158 | 91 | 11.3 min | EC/β⁺ |
| Ho-159 | 92 | 33.05 min | EC/β⁺ |
| Ho-160 | 93 | 25.6 min | EC/β⁺ |
| Ho-161 | 94 | 2.48 h | EC |
| Ho-162 | 95 | 15 min | EC/β⁺ |
| Ho-163 | 96 | 4570 a | EC |
| Ho-164 | 97 | 28.8 min | β⁻ |
| Ho-165 | 98 | stable | - |
| Ho-166 | 99 | 26.808 h | β⁻ |
| Ho-167 | 100 | 2.97 h | β⁻ |
| Ho-168 | 101 | 2.99 min | β⁻ |
| Ho-169 | 102 | 4.7 min | β⁻ |
| Ho-170 | 103 | 2.76 min | β⁻ |
| Ho-171 | 104 | 53 s | β⁻ |
| Ho-172 | 105 | 25 s | β⁻ |
| Ho-173 | 106 | 7.1 s | β⁻ |
| Ho-174 | 107 | 3.5 s | β⁻ |
| Ho-175 | 108 | 1.9 s | β⁻ |
| Ho-176 | 109 | unknown | β⁻ |
| Ho-177 | 110 | unknown | β⁻ |
| Ho-178 | 111 | unknown | β⁻ |
Data sources
- PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
- IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
- NIST Atomic Spectra Database (ASD) - Retrieved on 29 June 2026 - licence: © U.S. Secretary of Commerce
- Images of Elements - Retrieved on 29 June 2026 - licence: CC BY 3.0