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Pronunciation | (GAL-ee-əm) |
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Appearance | silvery blue |
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| 69.723(1)[1] |
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Atomic number (Z) | 31 |
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Group | group 13 (boron group) |
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Period | period 4 |
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Block | p-block |
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Electron configuration | [Ar] 3d10 4s2 4p1 |
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Electrons per shell | 2, 8, 18, 3 |
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Phase at STP | solid |
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Melting point | 302.9146 K (29.7646 °C, 85.5763 °F) |
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Boiling point | 2673 K (2400 °C, 4352 °F)[2] |
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Density (near r.t.) | 5.91 g/cm3 |
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when liquid (at m.p.) | 6.095 g/cm3 |
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Heat of fusion | 5.59 kJ/mol |
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Heat of vaporization | 256 kJ/mol[2] |
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Molar heat capacity | 25.86 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1310 |
1448 |
1620 |
1838 |
2125 |
2518 |
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Oxidation states | −5, −4, −3,[3] −2, −1, 0, +1, +2, +3[4] (an amphoteric oxide) |
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Electronegativity | Pauling scale: 1.81 |
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Ionization energies | - 1st: 578.8 kJ/mol
- 2nd: 1979.3 kJ/mol
- 3rd: 2963 kJ/mol
- (more)
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Atomic radius | empirical: 135 pm |
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Covalent radius | 122±3 pm |
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Van der Waals radius | 187 pm |
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Spectral lines of gallium |
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Natural occurrence | primordial |
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Crystal structure | orthorhombic |
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Speed of sound thin rod | 2740 m/s (at 20 °C) |
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Thermal expansion | 18 µm/(m⋅K) (at 25 °C) |
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Thermal conductivity | 40.6 W/(m⋅K) |
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Electrical resistivity | 270 nΩ⋅m (at 20 °C) |
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Magnetic ordering | diamagnetic |
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Molar magnetic susceptibility | −21.6×10−6 cm3/mol (at 290 K)[5] |
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Young's modulus | 9.8 GPa |
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Poisson ratio | 0.47 |
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Mohs hardness | 1.5 |
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Brinell hardness | 56.8–68.7 MPa |
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CAS Number | 7440-55-3 |
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Naming | after Gallia (Latin for: France), homeland of the discoverer |
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Prediction | Dmitri Mendeleev (1871) |
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Discovery and first isolation | Lecoq de Boisbaudran (1875) |
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Main isotopes[6] |
Decay |
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abundance |
half-life (t1/2) |
mode |
product |
66Ga |
synth |
9.5 h |
β+ |
66Zn |
67Ga |
synth |
3.3 d |
ε |
67Zn |
68Ga |
synth |
1.2 h |
β+ |
68Zn |
69Ga |
60.1% |
stable |
70Ga |
synth |
21 min |
β− |
70Ge |
ε |
70Zn |
71Ga |
39.9% |
stable |
72Ga |
synth |
14.1 h |
β− |
72Ge |
73Ga |
synth |
4.9 h |
β− |
73Ge |
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Category: Gallium | references |