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80. MercuryName: Mercury
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. Mercury was known to the ancient Chinese and Hindus and was found in Egyptian tombs that date from 1500s BC. By 500 BC it was used to make amalgams with other metals. The ancient Greeks used mercury in ointments and the Romans used it in cosmetics. Alchemists thought it to be the stuff from which all matter was formed and they also thought that when it hardened it turned into gold. In the 18th and 19th centuries, mercury nitrate was used to remove fur from the animal skins from which felt hats were made. This caused many cases of brain damage among hatters, or milliners, leading, it is claimed, to the simile "as mad as a hatter", and thereby to the Mad Hatter of Alice in Wonderland fame. It was named by alchemists after the Roman god Mercury. Its symbol Hg comes from hydrargyrum, a Latinised form of the Greek word hydrargyros, which was a compound word whose Greek roots meant 'water' and 'silver'. Quick links
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