Gallium is solid at normal room temperatures but turns into a when slightly heated. Gallium is in a group of metals of mercury, cesium, and rubidium that has this unique property. Gallium is a liquid over a wide range of temperature and has one of the longest ranges for any metal. It also has a low vapor pressure even when put at high temperatures. With this property, gallium has found use in thermometers and manometers for high-temperature measurements. Gallium can expand close to 3% when it is turned into a solid.
The metal is relatively unreactive. It does not react with air or water at room temperature and is only slightly attacked by mineral acids; it is oxidized slowly when red-hot and reacts with water at high temperatures. Gallium has tendencies to supercool below its freezing point. Minerals acids only attack gallium with high-purity gallium but slowly. Gallium's toxicity looks to be in a low order, but the metal should definitely be handled with care until further data says so. This metal readily alloys with other most metals, and it has been used in making low-melting alloys. Gallium does not react with air or water at room temperature. It only is oxidized when the metal is red-hot and reacts with water at high temperatures.