What is Mercury? What are the properties?
What is Mercury? What are the properties, uses, occurrence, and history of the Mercury element?
Information about the Mercury element
Mercury, a silvery-white metallic element, is the only metal that is liquid at room temperature. It flows so readily that it sometimes is called quicksilver. The symbol for mercury, Hg, is from the Latin hydrargyrum, which means liquid silver. The metal was known to the ancient Chinese, Hindus, Egyptians, Greeks, and Romans.
Mercury has an atomic number of 80 and an atomic weight of 200.59. It is in group Ilb of the periodic table, as are cadmium and zinc.
Uses. A majör use of mercury is in electrical equipment such as fluorescent lamps, mercury-vapor ultraviolet lamps, switches and relays, and mercury batteries. Mercury is also used in cells for producing chlorine and caustic soda electrolytically. Another majör use is in paints to make them mildew proof. The low freezing point of mercury and its even expansion with heat make it useful in thermometers, and its high density makes it useful in barometers and blood pressure recorders. Other uses of mercury include catalysts for the chemical industry, agricultural fungicides, silver-mercury alloys for filling teeth, and pharmaceuticals. In medicine, mercury compounds have been used as diuretics, fungicides, and antiseptics (mercurochrome).
Properties and Compounds. Mercury has seven stable isotopes. The mass number and proportion of each isotope are: 204, 8.8%; 202, 29.8%; 201, 13.2%; 200, 23.1%; 199, 16.9%; 198, 10%; and 196, 0.15%. In addition, several radioactive isotopes of mercury have been produced artificially.
Mercury remains liquid över a wide temperature range. Under atmospheric pressure, its melting point is —38.87°C ( -38°F), and its boiling point is 356.57°C (673.8°F). its density at room temperature is 13.546. Mercury has a relatively large and linear thermal expansion över a wide range of temperatures, and it does not wet glass because of its high surface tension. These properties make it useful in thermometers.
Mercury compounds fail into two groups. In one group, the mercury has a +1 oxidation number. Those compounds are called mercurous compounds or mercury (I) compounds. Two members of this group are mercurous chloride, Hg2Cl2, and mercurous sulfate, Hg2SO4. In the second group, mercury has a +2 oxidation number. These compounds are called mercuric compounds of mercury (II) compounds. Two members of this group are mercuric chloride, HgCl2, and mercuric oxide, HgO.
Mercury forms alloys with gold, silver, copper, lead, and several other metals. An alloy of mercury and another metal is called an amalgam.
Extraction and Purification.
The extractİon of mercury from the mercuric sulfide ore is accomplished mainly by roasting the sulfide in the air in an îurnace. In this reaction, the sulfide is oxidized to sulfur dioxide, and freed mercury vapor and other products are condensed as mercurial soot in a water-cooled metal condenser. The mercury metal then is separated from the soot by filtration or mechanical agitation. Final purification of the metal can be achieved by vacuum distillation.