|Molecular Weight||69.72 g/mol|
|Melting Point||29.76 °C|
|Boiling Point||2,400 °C|
Solid gallium is a gray-blue metal with an orthorhombic crystal structure; the purest gallium has a splendid silvery color. Gallium is solid at room temperature, but like mercury, cesium, and rubidium, it becomes liquid when heated slightly. Hard gallium is soft enough to be cut with a knife. Stable in air and water; but it reacts with acids and alkalis and dissolves in them. Liquid gallium wets porcelain and glass surfaces; when applied to glass, it forms a bright and highly reflective surface. It can be used to create glossy mirrors. Gallium binds easily with most metals, therefore it is used to obtain low melting alloys. Nuclear weapon plutonium sinks use a gallium alloy to stabilize plutonium allotropes. Analog ICs are the most common application for gallium, and optoelectronic devices (mainly laser diodes and light-emitting diodes) are the second-largest end-use. Gallium has semiconductive properties, notably gallium arsenites (GaAs). It can convert electricity into light and is used in light-emitting diodes (LEDs) for electronic displays and watches. Gallium is used in some high-temperature thermometers. Gallium does not exist in its pure form in nature and gallium compounds are not the main source of extraction. Gallium is more abundant than lead, but much less available because it has not been selectively concentrated into minerals by any geological process, so it tends to be widely dispersed. Some minerals, such as aluminum bauxite ore, contain small amounts of gallium, while coal can have a relatively high gallium content.