Galinstan

Galinstan is an alloy of Gallium, Indium, and Tin which is liquid at room temperature, typically freezing at below 20 degrees Celsius. 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.

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.