67HoHolmium164.930328 u
Holmium (Ho)
Holmium is a lanthanide with atomic number 67, in period 6, in the f-block of the periodic table. Its atomic mass is 164.930328 u and its electron configuration is [Xe] 4f¹¹ 6s². Solid at 25 °C.
Key facts
| Atomic number | 67 |
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| Atomic mass | 164.930328 u |
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| Category | Lanthanide |
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| Period | 6 |
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| Group | f-block, no group number |
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| Block | f |
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| Electron configuration | [Xe] 4f¹¹ 6s² |
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| Electrons per shell | 2, 8, 18, 29, 8, 2 |
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| Electronegativity (Pauling) | 1.23 |
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| Oxidation states | +2, +3common in bold |
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| State at 25 °C | Solid |
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| Melting point | 1747 K1473.85 °C |
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| Boiling point | 2973 K2699.85 °C |
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| Density | 8.795 g/cm³ |
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Atomic properties
| First ionization energy | 6.022 eV |
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| Electron affinity | 50 kJ/mol |
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| Atomic radius | 179 pm |
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| Covalent radius | 192 pm |
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| Van der Waals radius | 216 pm |
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| Common ions | Ho³⁺ |
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| Protons, neutrons, electrons | 67, 98, 67 |
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Physical and thermal properties
| Molar volume | 18.74 cm³/mol |
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| Heat of fusion | 17 kJ/mol |
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| Heat of vaporization | 265 kJ/mol |
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| Specific heat | 165 J/(kg·K) |
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| Thermal conductivity | 16 W/(m·K) |
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| Thermal expansion | 1.12 × 10⁻⁵ K⁻¹ |
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| Mohs hardness | 1.65 |
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| Young’s modulus | 64 GPa |
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| Crystal structure | Simple hexagonal |
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| Magnetic type | Paramagnetic |
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Identification and history
| CAS number | 7440-60-0 |
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| Latin name | Holmium |
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| Discovered by | Jacques-Louis Soret · 1878 |
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| Named by | --- |
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Natural isotopes
| Isotope | Mass (u) | Abundance |
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| 165Ho | 164.930329 | 100 % |
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
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Periodic Table