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| Pronunciation | (SIL-ə-kən) |
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| Appearance | crystalline, reflective with bluish-tinged faces |
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| Standard atomic weight (Ar, standard) | [28.084, 28.086] |
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| Atomic number (Z) | 14 |
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| Group | group 14 (carbon group) |
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| Period | period 3 |
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| Block | p-block |
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| Element category | metalloid |
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| Electron configuration | [Ne] 3s2 3p2 |
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Electrons per shell | 2, 8, 4 |
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| Phase at STP | Si: Solid |
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| Melting point | 1687 K (1414 °C, 2577 °F) |
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| Boiling point | 3538 K (3265 °C, 5909 °F) |
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| Density (near r.t.) | 2.3290 g/cm3 |
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| when liquid (at m.p.) | 2.57 g/cm3 |
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| Heat of fusion | 50.21 kJ/mol |
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| Heat of vaporization | 383 kJ/mol |
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| Molar heat capacity | 19.789 J/(mol·K) |
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Vapor pressure| P (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k |
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| at T (K) | 1908 | 2102 | 2339 | 2636 | 3021 | 3537 |
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| Oxidation states | −4, −3, −2, −1, +1 +2, +3, +4 (an amphoteric oxide) |
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| Electronegativity | Pauling scale: 1.90 |
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| Ionization energies | - 1st: 786.5 kJ/mol
- 2nd: 1577.1 kJ/mol
- 3rd: 3231.6 kJ/mol
- (more)
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| Atomic radius | empirical: 111 pm |
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| Covalent radius | 111 pm |
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| Van der Waals radius | 210 pm |
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| Spectral lines of silicon |
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| Natural occurrence | Si: Primordial |
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| Crystal structure | face-centered diamond-cubic |
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| Speed of sound thin rod | 8433 m/s (at 20 °C) |
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| Thermal expansion | 2.6 µm/(m·K) (at 25 °C) |
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| Thermal conductivity | 149 W/(m·K) |
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| Electrical resistivity | 2.3×103 Ω·m (at 20 °C) |
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| Band gap | 1.12 eV (at 300 K) |
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| Magnetic ordering | diamagnetic |
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| Magnetic susceptibility | −3.9·10−6 cm3/mol (298 K) |
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| Young's modulus | 130–188 GPa |
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| Shear modulus | 51–80 GPa |
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| Bulk modulus | 97.6 GPa |
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| Poisson ratio | 0.064–0.28 |
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| Mohs hardness | 6.5 |
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| CAS Number | 7440-21-3 |
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| Naming | after Latin 'silex' or 'silicis', meaning flint |
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| Prediction | Antoine Lavoisier (1787) |
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| Discovery and first isolation | Jöns Jacob Berzelius (1823) |
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| Named by | Thomas Thomson (1817) |
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