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Pronunciation | (mə-LIB-də-nəm) |
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Appearance | gray metallic |
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| 95.95(1)[1] |
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Atomic number (Z) | 42 |
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Group | group 6 |
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Period | period 5 |
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Block | d-block |
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Electron configuration | [Kr] 4d5 5s1 |
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Electrons per shell | 2, 8, 18, 13, 1 |
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Phase at STP | solid |
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Melting point | 2896 K (2623 °C, 4753 °F) |
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Boiling point | 4912 K (4639 °C, 8382 °F) |
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Density (near r.t.) | 10.28 g/cm3 |
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when liquid (at m.p.) | 9.33 g/cm3 |
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Heat of fusion | 37.48 kJ/mol |
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Heat of vaporization | 598 kJ/mol |
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Molar heat capacity | 24.06 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
2742 |
2994 |
3312 |
3707 |
4212 |
4879 |
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Oxidation states | −4, −2, −1, 0, +1,[2] +2, +3, +4, +5, +6 (a strongly acidic oxide) |
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Electronegativity | Pauling scale: 2.16 |
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Ionization energies | - 1st: 684.3 kJ/mol
- 2nd: 1560 kJ/mol
- 3rd: 2618 kJ/mol
-
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Atomic radius | empirical: 139 pm |
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Covalent radius | 154±5 pm |
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Spectral lines of molybdenum |
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Natural occurrence | primordial |
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Crystal structure | body-centered cubic (bcc) |
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Speed of sound thin rod | 5400 m/s (at r.t.) |
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Thermal expansion | 4.8 µm/(m⋅K) (at 25 °C) |
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Thermal conductivity | 138 W/(m⋅K) |
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Thermal diffusivity | 54.3 mm2/s (at 300 K)[3] |
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Electrical resistivity | 53.4 nΩ⋅m (at 20 °C) |
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Magnetic ordering | paramagnetic[4] |
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Molar magnetic susceptibility | +89.0×10−6 cm3/mol (298 K)[5] |
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Young's modulus | 329 GPa |
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Shear modulus | 126 GPa |
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Bulk modulus | 230 GPa |
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Poisson ratio | 0.31 |
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Mohs hardness | 5.5 |
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Vickers hardness | 1400–2740 MPa |
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Brinell hardness | 1370–2500 MPa |
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CAS Number | 7439-98-7 |
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Discovery | Carl Wilhelm Scheele (1778) |
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First isolation | Peter Jacob Hjelm (1781) |
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Main isotopes[6] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
92Mo |
14.7% |
stable |
93Mo |
synth |
4×103 y |
ε |
93Nb |
94Mo |
9.19% |
stable |
95Mo |
15.9% |
stable |
96Mo |
16.7% |
stable |
97Mo |
9.58% |
stable |
98Mo |
24.3% |
stable |
99Mo |
synth |
65.94 h |
β− |
99mTc |
γ |
– |
100Mo |
9.74% |
7.1×1018 y |
β−β− |
100Ru |
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Category: Molybdenum | references |