Galinstan

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Galinstan is an eutectic alloy of gallium, indium, and tin which is liquid at room temperature, typically freezing at -20 °C (-4 °F). Due to the low toxicity of its component metals, it finds use as a non-toxic replacement for many applications which currently employ liquid mercury or sodium-potassium alloy (NaK). Composition: 68.5% Ga, 21.5% In, 10% Sn. Its name is a portmanteau of gallium, indium, and stannum (Latin for "tin").

1 Physical properties
2 See also
3 Reference
4 External link

[edit] Physical properties

Galinstan from a broken thermometer, easily wetting a piece of glass.

Boiling point: > 1300 °C
Melting point: - 19 °C
Vapour pressure: at 500 °C < 10-8 Torr
Density: 6.44 g/cm³
Solubility: Insoluble in water or organic solvents

Galinstan tends to wet and adhere to many materials, including glass, which limits its use compared to mercury. Galinstan thermometers can be made if the inner tube is first coated with gallium oxide to prevent the alloy from wetting the glass surface.

Galinstan is commercially used as a mercury replacement in thermometers due to its nontoxic properties.

Galinstan has higher reflectivity and lower density than mercury; it is investigated as a replacement of mercury in liquid mirror telescopes for astronomy. It is also a promising coolant, though its cost and aggressivity are major obstacles for its use.

Galinstan is difficult to use for cooling nuclear reactors, because indium has high cross section for thermal neutrons, efficiently absorbing them and inhibiting the fission reaction.