Graphite (left) and diamond (right), two allotropes of carbon |
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Allotropes | graphite, diamond |
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Appearance | graphite: black diamond: clear |
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Standard atomic weight (Ar, standard) | [12.0096, 12.0116] |
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Atomic number (Z) | 6 |
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Group | group 14 (carbon group) |
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Period | period 2 |
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Block | p-block |
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Element category | reactive nonmetal, sometimes considered a metalloid |
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Electron configuration | [He] 2s2 2p2 |
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Electrons per shell | 2, 4 |
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Phase at STP | C: Solid |
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Sublimation point | 3915 K (3642 °C, 6588 °F) |
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Density (near r.t.) | amorphous: 1.8–2.1 g/cm3 graphite: 2.267 g/cm3 diamond: 3.515 g/cm3 |
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Triple point | 4600 K, 10,800 kPa |
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Heat of fusion | graphite: 117 kJ/mol |
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Molar heat capacity | graphite: 8.517 J/(mol·K) diamond: 6.155 J/(mol·K) |
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Oxidation states | −4, −3, −2, −1, 0, +1, +2, +3,+4 (a mildly acidic oxide) |
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Electronegativity | Pauling scale: 2.55 |
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Ionization energies | - 1st: 1086.5 kJ/mol
- 2nd: 2352.6 kJ/mol
- 3rd: 4620.5 kJ/mol
- (more)
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Covalent radius | sp3: 77 pm sp2: 73 pm sp: 69 pm |
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Van der Waals radius | 170 pm |
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Spectral lines of carbon |
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Natural occurrence | C: Primordial |
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Crystal structure | graphite: simple hexagonal (black) |
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Crystal structure | diamond: face-centered diamond-cubic (clear) |
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Speed of sound thin rod | diamond: 18,350 m/s (at 20 °C) |
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Thermal expansion | diamond: 0.8 µm/(m·K) (at 25 °C) |
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Thermal conductivity | graphite: 119–165 W/(m·K) diamond: 900–2300 W/(m·K) |
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Electrical resistivity | graphite: 7.837 µΩ·m |
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Magnetic ordering | diamagnetic |
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Magnetic susceptibility | −5.9·10−6 (graph.) cm3/mol |
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Young's modulus | diamond: 1050 GPa |
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Shear modulus | diamond: 478 GPa |
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Bulk modulus | diamond: 442 GPa |
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Poisson ratio | diamond: 0.1 |
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Mohs hardness | graphite: 1–2 diamond: 10 |
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CAS Number | 7440-44-0 |
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Discovery | Egyptians and Sumerians (3750 BCE) |
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Recognized as an element by | Antoine Lavoisier (1789) |
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| references |