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Pronunciation | (HOHL-mee-əm) |
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Appearance | silvery white |
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| 164.930328(7)[1] |
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Atomic number (Z) | 67 |
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Group | f-block groups (no number) |
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Period | period 6 |
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Block | f-block |
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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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Phase at STP | solid |
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Melting point | 1734 K (1461 °C, 2662 °F) |
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Boiling point | 2873 K (2600 °C, 4712 °F) |
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Density (near r.t.) | 8.79 g/cm3 |
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when liquid (at m.p.) | 8.34 g/cm3 |
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Heat of fusion | 17.0 kJ/mol |
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Heat of vaporization | 251 kJ/mol |
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Molar heat capacity | 27.15 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1432 |
1584 |
(1775) |
(2040) |
(2410) |
(2964) |
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Oxidation states | 0,[2] +1, +2, +3 (a basic oxide) |
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Electronegativity | Pauling scale: 1.23 |
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Ionization energies | - 1st: 581.0 kJ/mol
- 2nd: 1140 kJ/mol
- 3rd: 2204 kJ/mol
-
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Atomic radius | empirical: 176 pm |
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Covalent radius | 192±7 pm |
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Spectral lines of holmium |
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Natural occurrence | primordial |
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Crystal structure | hexagonal close-packed (hcp) |
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Speed of sound thin rod | 2760 m/s (at 20 °C) |
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Thermal expansion | poly: 11.2 µm/(m⋅K) (at r.t.) |
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Thermal conductivity | 16.2 W/(m⋅K) |
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Electrical resistivity | poly: 814 nΩ⋅m (at r.t.) |
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Magnetic ordering | paramagnetic |
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Young's modulus | 64.8 GPa |
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Shear modulus | 26.3 GPa |
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Bulk modulus | 40.2 GPa |
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Poisson ratio | 0.231 |
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Vickers hardness | 410–600 MPa |
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Brinell hardness | 500–1250 MPa |
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CAS Number | 7440-60-0 |
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Discovery | Per Theodor Cleve, Jacques-Louis Soret and Marc Delafontaine (1878) |
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Main isotopes[3] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
163Ho |
synth |
4570 y |
ε |
163Dy |
164Ho |
synth |
28.8 min |
ε |
164Dy |
β− |
164Er |
165Ho |
100% |
stable |
166Ho |
synth |
26.812 h |
β− |
166Er |
166m1Ho |
synth |
1132.6 y |
β− |
166Er |
167Ho |
synth |
3.1 h |
β− |
167Er |
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Category: Holmium | references |