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For thermometers. | Atomic Number: | 80 | Atomic Symbol: | Hg | | Atomic Weight: | 200.59 | Electron Configuration: | 2-8-18-32-18-2 | | Shells: | 2,8,18,32,18,2 | Filling Orbital: | 5d10 | | Melting Point: | -38.87oC | Boiling Point: | 356.58oC | | Description: | Silver colored liquid metal. |
| Uses: | Used in thermometers, barometers, flourescent lamps and batteries. |
History(Planet Mercury) Known to ancient Chinese and Hindus; found in
Egyptian tombs of 1500 B.C. Mercury is the only common metal liquid at ordinary
temperatures. It only rarely occurs free in nature. The chief ore is cinnabar,
Spain and Italy produce about 50% of the world's supply of the metal. The
commercial unit for handling mercury is the "flask," which weighs 76 lb. The
metal is obtained by heating cinnabar in a current of air and by condensing the
vapor. It is a heavy, silvery-white metal; a rather poor conductor of heat, as
compared with other metals, and a fair conductor of electricity. It easily forms
alloys with many metals, such as gold, silver, and tin, which are called
amalgams. Its ease in amalgamating with gold is made us of in the recovery of
gold from its ores. The metal is widely used in laboratory work for making
thermometers, barometers, diffusion pumps, and many other instruments. It is
used in making mercury-vapor lamps and advertising signs, etc. and is used in
mercury switches and other electronic apparatus. Other uses are in making
pesticides, cercury cells for caustic soda and chlorine production, dental
preparations, antifouling paint, batteries, and catalysts. The most important
salts are mercury chloride (corrosive sublimate - a violent poison), mercurous
chloride (calomel, occasionally still used in medicine), mercury fulminate, a
detonator widely used in explosives, and mercuric sulfide (vermillion, a
high-grade paint pigment). Organic mercury compounds are important. It has been
found that an electrical discharge causes mercury vapor to combine with neon,
argon, krypton, and xenon. These products, held together with van der Waals'
forces, correspond to HgNe, HgAr, HgKr, and HgXe. Mercury is a virulent poison
and is readily absorbed through the respiratory tract, the gastrointestinal
tract, or through unbroken skin. It acts as a cumulative poison and dangerous
levels are readily attained in air. Air saturated with mercury vapor at 20C
contains a concentration that exceeds the toxic limit many times. 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. It it is necessary to heat mercury or mercury compounds, it
should be done in a well-ventilated hood. Methyl mercury is a dangerous
pollutant and is now widely found in water and streams. The triple point of
mercury, -38.8344C, is a fixed point on the International Temperature Scale
(ITS-90).
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