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Pronunciation | |
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Alternative name | aluminum (U.S., Canada) |
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Appearance | silvery gray metallic |
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Standard atomic weight (Ar, standard) | 26.9815384(3) |
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Atomic number (Z) | 13 |
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Group | group 13 (boron group) |
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Period | period 3 |
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Block | p-block |
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Element category | post-transition metal, sometimes considered a metalloid |
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Electron configuration | [Ne] 3s2 3p1 |
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Electrons per shell | 2, 8, 3 |
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Phase at STP | Al: Solid |
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Melting point | 933.47 K (660.32 °C, 1220.58 °F) |
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Boiling point | 2743 K (2470 °C, 4478 °F) |
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Density (near r.t.) | 2.70 g/cm3 |
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when liquid (at m.p.) | 2.375 g/cm3 |
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Heat of fusion | 10.71 kJ/mol |
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Heat of vaporization | 284 kJ/mol |
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Molar heat capacity | 24.20 J/(mol·K) |
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Vapor pressureP (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k |
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at T (K) | 1482 | 1632 | 1817 | 2054 | 2364 | 2790 |
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Oxidation states | −2, −1, +1, +2,+3 (an amphoteric oxide) |
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Electronegativity | Pauling scale: 1.61 |
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Ionization energies | - 1st: 577.5 kJ/mol
- 2nd: 1816.7 kJ/mol
- 3rd: 2744.8 kJ/mol
- (more)
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Atomic radius | empirical: 143 pm |
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Covalent radius | 121±4 pm |
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Van der Waals radius | 184 pm |
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Spectral lines of aluminium |
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Natural occurrence | Al: Primordial |
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Crystal structure | face-centered cubic (fcc) |
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Speed of sound thin rod | (rolled) 5000 m/s (at r.t.) |
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Thermal expansion | 23.1 µm/(m·K) (at 25 °C) |
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Thermal conductivity | 237 W/(m·K) |
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Electrical resistivity | 26.5 nΩ·m (at 20 °C) |
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Magnetic ordering | paramagnetic |
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Magnetic susceptibility | +16.5·10−6 cm3/mol |
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Young's modulus | 70 GPa |
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Shear modulus | 26 GPa |
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Bulk modulus | 76 GPa |
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Poisson ratio | 0.35 |
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Mohs hardness | 2.75 |
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Vickers hardness | 160–350 MPa |
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Brinell hardness | 160–550 MPa |
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CAS Number | 7429-90-5 |
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Naming | after alumina (aluminium oxide), itself named after mineral alum |
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Prediction | Antoine Lavoisier (1782) |
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Discovery and first isolation | Hans Christian Ørsted (1824) |
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Named by | Humphry Davy (1812) |
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| references |