Mercury makes liquid alloys with gold, silver, copper and lead. Mercury gives off a toxic vapour when exposed to the air, even at temperatures well below its boiling point. This limits its uses in many applications. The main uses for mercury are as amalgams and in thermometers and barometers. Amalgams An amalgam is a mixture, or liquid alloy, of metals with mercury.
Amalgams are extremely useful.
Amalgams have been used for extracting precious metals such as gold and silver from their ores. They are used widely in industry and in dentistry, where the metal fillings are amalgams with silver or gold. When mercury is dropped on to the surface of a thin sheet of shiny aluminium, the two elements form an amalgam. Because the sheet is thin, all the aluminium mixes with the mercury at the places where the mercury droplets settle. The result is a pattern of holes where the aluminium has simply become part of the amalgam, which then falls away.