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Molybdenum |
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Pronunciation | (mə-LIB-din-əm) |
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Appearance | gray metallic |
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Standard atomic weight Ar, std(Mo) | 7001959500000000000♠95.95(1)[1] |
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Molybdenum in the periodic cairt |
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Atomic nummer (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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Element category | Transeetion metal |
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Electron confeeguration | [Kr] 4d5 5s1 |
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Electrons per shell | 2, 8, 18, 13, 1 |
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Pheesical properties |
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Phase at STP | solit |
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Meltin pynt | 2896 K (2623 °C, 4753 °F) |
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Bylin pynt | 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 o fusion | 37.48 kJ/mol |
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Heat o vapourisation | 598 kJ/mol |
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Molar heat capacity | 24.06 J/(mol·K) |
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Vapour pressur
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
2742 |
2994 |
3312 |
3707 |
4212 |
4879 |
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Atomic properties |
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Oxidation states | −4, −2, −1, 0, +1,[2] +2, +3, +4, +5, +6 strangly acidic |
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Electronegativity | Pauling scale: 2.16 |
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Atomic radius | empirical: 139 pm |
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Covalent radius | 154±5 pm |
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Spectral lines o molybdenum |
Ither properties |
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Naitural occurrence | primordial |
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Creestal structur | body-centred cubic (bcc) |
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Speed o soond 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[3] mm2/s (at 300 K) |
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Electrical resistivity | 53.4 n Ω·m (at 20 °C) |
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Magnetic orderin | paramagnetic[4] |
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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 haurdness | 5.5 |
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Vickers haurdness | 1530 MPa |
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Brinell haurdness | 1500 MPa |
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CAS Nummer | 7439-98-7 |
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History |
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Diskivery | Carl Wilhelm Scheele (1778) |
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First isolation | Peter Jacob Hjelm (1781) |
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Main isotopes o molybdenum |
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Isotope |
Abundance |
Hauf-life (t1/2) |
Decay mode |
Product |
92Mo |
14.84% |
>1.9×1020 y |
(β+β+) |
92Zr |
93Mo |
syn |
4×103 y |
ε |
93Nb |
94Mo |
9.25% |
- |
(SF) |
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95Mo |
15.92% |
- |
(SF) |
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96Mo |
16.68% |
- |
(SF) |
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97Mo |
9.55% |
- |
(SF) |
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98Mo |
24.13% |
>1×1014 y |
β−β− |
98Ru |
99Mo |
syn |
65.94 h |
β− |
99mTc |
γ |
- |
100Mo |
9.63% |
7.8×1018 y |
(β−β−) |
100Ru |
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Decay modes in parentheses is predict, but hisna yet been observed |
| references |