Name: mercury
Symbol: Hg
Atomic number: 80
Atomic weight: 200.59 (2)
Group in periodic table: 12
Group name:
Period in periodic table: 6
Block in periodic table: d-block
CAS registry ID: 7439-97-6
Mercury is the only common metal liquid at ordinary temperatures. Mercury is sometimes called quicksilver. It rarely occurs free in nature and is found mainly in cinnabar ore (HgS) in Spain and Italy. It is a heavy, silvery-white liquid metal. It is a rather poor conductor of heat as compared with other metals but is a fair conductor of electricity. It alloys easily with many metals, such as gold, silver, and tin. These alloys are called amalgams. Its ease in amalgamating with gold is made use of in the recovery of gold from its ores.
The most important salts are mercuric chloride HgC12 (corrosive sublimate - a violent poison), mercurous chloride Hg2Cl2 (calomel, occasionally still used in medicine), mercury fulminate (Hg(ONC)2, a detonator used in explosives), and mercuric sulphide (HgS, vermillion, a high-grade paint pigment).
Organic mercury compounds are important - and dangerous. Methyl mercury is a lethal pollutant found in rivers and lakes. The main source of pollution is industrial wastes settling to the river and lake bottoms.
As mercury is a very volatile element, dangerous levels are readily attained in air. Mercury vapour should not exceed 0.1 mg m-3 in air. Air saturated with the vapour at 20°C contains mercury in a concentration far greater than that limit. The danger increases at higher temperatures. It is therefore important that mercury be handled with care. Containers of mercury should be securely covered and spillage should be avoided. Mercury should only be handled under in a well-ventilated area. If you are in possession of any mercury you are advised to contact a properly qualified chemist or public health laboratory for its safe disposal.
Small amounts of mercury spillage can be cleaned up by addition of sulphur powder. The resulting mixture should be disposed of carefully.