Gallium

Gallium, ₃₁Ga
Gallium
Pronunciation	/ˈɡæliəm/ (GAL-ee-əm)
Appearance	silver-white
Standard atomic weight Ar, std(Ga)	69.723(1)
Gallium in the periodic cairt
	zinc ← gallium → germanium
Atomic nummer (Z)	31
Group	group 13 (boron group)
Period	period 4
Block	p-block
Element category	Post-transeetion metal
Electron confeeguration	[Ar] 3d10 4s2 4p1
Electrons per shell	2, 8, 18, 3
Pheesical properties
Phase at STP	solit
Meltin pynt	302.9146 K (29.7646 °C, 85.5763 °F)
Bylin pynt	2477 K (2204 °C, 3999 °F)
Density (near r.t.)	5.91 g/cm3
when liquid (at m.p.)	6.095 g/cm3
Heat o fusion	5.59 kJ/mol
Heat o vapourisation	254 kJ/mol
Molar heat capacity	25.86 J/(mol·K)
Atomic properties
Oxidation states	−5, −4, −3, −2, −1, +1, +2, +3 (an amphoteric oxide)
Electronegativity	Pauling scale: 1.81
Ionisation energies	(more);
Atomic radius	empirical: 135 pm
Covalent radius	122±3 pm
Van der Waals radius	187 pm
	Colour lines in a spectral rangeSpectral lines o gallium
Ither properties
Naitural occurrence	primordial
Creestal structur	orthorhombic
Speed o soond thin rod	2740 m/s (at 20 °C)
Thermal expansion	18 µm/(m·K) (at 25 °C)
Thermal conductivity	40.6 W/(m·K)
Electrical resistivity	270 n Ω·m (at 20 °C)
Magnetic orderin	diamagnetic
Young's modulus	9.8 GPa
Poisson ratio	0.47
Mohs haurdness	1.5
Brinell haurdness	60 MPa
CAS Nummer	7440-55-3
History
Prediction	Dmitri Mendeleev (1871)
Diskivery	Lecoq de Boisbaudran (1875)
First isolation	Lecoq de Boisbaudran (1875)
Main isotopes o gallium
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Gallium is a chemical element wi seembol Ga an atomic nummer 31. Elemental gallium disnae occur in free furm in naitur, but as the gallium(III) compoonds that is in trace amoonts in zinc ores an in bauxite. Gallium is a saft sillery metal, an elemental gallium is a brickle solit at law temperaturs. Gif it is held in the human haund lang eneuch, gallium will melt, syne it melts at the temperatur o aboot 29.76 °C (85.57 °F) (slichtly abuin ruim temperatur). The meltin pynt o gallium is uised as a temperatur reference pynt. The alloy galinstan (68.5% gallium, 21.5% indium, an 10% tin) haes the even lawer meltin pynt o −19 °C (−2 °F), weel ablo the freezin pynt o watter. Beginnin wi its discovery in 1875 throu the era o semiconductors, gallium wis uised primarily as an agent tae mak alloys that melt at law temperaturs. Then, gallium became uiseful in semiconductors, includin as a dopant.

References

↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
↑ Ga(−3) has been observed in LaGa, see Dürr, Ines; Bauer, Britta; Röhr, Caroline (2011). "Lanthan-Triel/Tetrel-ide La(Al,Ga)_x(Si,Ge)_1-x. Experimentelle und theoretische Studien zur Stabilität intermetallischer 1:1-Phasen" (PDF). Z. Naturforsch. (in German). 66b: 1107–1121.
↑ Hofmann, Patrick (1997). Colture. Ein Programm zur interaktiven Visualisierung von Festkörperstrukturen sowie Synthese, Struktur und Eigenschaften von binären und ternären Alkali- und Erdalkalimetallgalliden (PDF) (in German). PhD Thesis, ETH Zurich. p. 72. doi:10.3929/ethz-a-001859893. ISBN 978-3728125972.

[CIAAW2013-1] Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

[2] Ga(−3) has been observed in LaGa, see Dürr, Ines; Bauer, Britta; Röhr, Caroline (2011). "Lanthan-Triel/Tetrel-ide La(Al,Ga)_x(Si,Ge)_1-x. Experimentelle und theoretische Studien zur Stabilität intermetallischer 1:1-Phasen" (PDF). Z. Naturforsch. (in German). 66b: 1107–1121.

[3] Hofmann, Patrick (1997). Colture. Ein Programm zur interaktiven Visualisierung von Festkörperstrukturen sowie Synthese, Struktur und Eigenschaften von binären und ternären Alkali- und Erdalkalimetallgalliden (PDF) (in German). PhD Thesis, ETH Zurich. p. 72. doi:10.3929/ethz-a-001859893. ISBN 978-3728125972.

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