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Pronunciation | (ROH-dee-əm) |
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Appearance | silvery white metallic |
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| 102.90549(2)[1] |
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Atomic number (Z) | 45 |
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Group | group 9 |
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Period | period 5 |
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Block | d-block |
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Electron configuration | [Kr] 4d8 5s1 |
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Electrons per shell | 2, 8, 18, 16, 1 |
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Phase at STP | solid |
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Melting point | 2237 K (1964 °C, 3567 °F) |
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Boiling point | 3968 K (3695 °C, 6683 °F) |
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Density (near r.t.) | 12.41 g/cm3 |
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when liquid (at m.p.) | 10.7 g/cm3 |
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Heat of fusion | 26.59 kJ/mol |
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Heat of vaporization | 493 kJ/mol |
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Molar heat capacity | 24.98 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
2288 |
2496 |
2749 |
3063 |
3405 |
3997 |
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Oxidation states | −3[2], −1, 0, +1,[3] +2, +3, +4, +5, +6, +7[4] (an amphoteric oxide) |
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Electronegativity | Pauling scale: 2.28 |
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Ionization energies | - 1st: 719.7 kJ/mol
- 2nd: 1740 kJ/mol
- 3rd: 2997 kJ/mol
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Atomic radius | empirical: 134 pm |
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Covalent radius | 142±7 pm |
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Spectral lines of rhodium |
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Natural occurrence | primordial |
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Crystal structure | face-centered cubic (fcc) |
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Speed of sound thin rod | 4700 m/s (at 20 °C) |
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Thermal expansion | 8.2 µm/(m⋅K) (at 25 °C) |
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Thermal conductivity | 150 W/(m⋅K) |
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Electrical resistivity | 43.3 nΩ⋅m (at 0 °C) |
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Magnetic ordering | paramagnetic[5] |
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Molar magnetic susceptibility | +111.0×10−6 cm3/mol (298 K)[6] |
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Young's modulus | 380 GPa |
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Shear modulus | 150 GPa |
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Bulk modulus | 275 GPa |
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Poisson ratio | 0.26 |
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Mohs hardness | 6.0 |
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Vickers hardness | 1100–8000 MPa |
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Brinell hardness | 980–1350 MPa |
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CAS Number | 7440-16-6 |
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Discovery and first isolation | William Hyde Wollaston (1804) |
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Main isotopes[7] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
99Rh |
synth |
16.1 d |
β+ |
99Ru |
101Rh |
synth |
4.07 y |
ε |
101Ru |
101mRh |
synth |
4.343 d |
ε |
101Ru |
IT |
101Rh |
102Rh |
synth |
207 d |
β+ |
102Ru |
β− |
102Pd |
102mRh |
synth |
3.742 y |
β+ |
102Ru |
IT |
102Rh |
103Rh |
100% |
stable |
105Rh |
synth |
35.341 h |
β− |
105Pd |
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Category: Rhodium | references |