What Is Quicksilver?

Quicksilver or liquid silver is an old name for mercury, an element that is a free-flowing liquid at room temperature. Its atomic number is 80.
It was first made known as an element by French chemist Antoine Laurent Lavoisier. He burned mercury in his experiments to determine the composition of air. It is a shinning, movable liquid and silvery white at ordinary temperature. Mercury becomes solid when treated to a pressure of 7,640 atmospheres. It melts in nitric or concentrated sulfuric acid but is resistant to alkalis. When cooled to sufficiently low temperatures, mercury becomes a superconductor. Mercury freezes at about -39°C (about -38°F), and boils at about 357°C (about 674°F).
It is found in its pure form or in combination with silver in small amounts but occurs most often in the ore cinnabar, a mineral consisting of mercuric sulphide (HgS).
Mercury is used in thermometers because its change in volume for each degree of rise or fall in temperature is the same. It is also used in vacuum pumps, barometers, and electric rectifiers and switches. It is a toxic element and because of its toxicity its use has been on the decline in industries, including pharmaceuticals, dentistry, and agriculture.