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Bismuth, a silver-white metal, atomic number 83, atomic weight 208.980,
is the most
metallic element in the group 15 in the periodic table. Though the principal deposits are in ores,
the primary
source of bismuth is as a by-product in refining of copper
and lead ores. Of all the metals, bismuth is the most diamagnetic and has the lowest thermal conductivity except
mercury. Bismuth has a high electrical resistance
and the highest Hall coefficient. Elemental bismuth like antimony and water
is the substances of which the liquid phase is denser than its solid phase.
The field of application of our bismuth-based chemicals is found
in ceramic materials, pharmaceuticals, cosmetics, and automobile industry to
reduce the levels of lead. Bismuth telluride (Bi2Te3) and bismuth selenide (Bi2Se3)
are used in
thermoelectric equipment for refrigeration. Bismuth phosphomolybdate (BiPMo12O40)
is a highly
effective catalyst for the preparation of acrylonitrile, which is the raw
materials of acrylic fibres, plastics, and
paints. Bismuth chemicals are used in cosmetics for shiny look in eye shadow,
nail varnish and lipstick due to metallic and pearlescent effect.
Salts of bismuth have astringent, antacid, and mildly germicidal properties and are used to
treat diarrhea, nausea, indigestion, and other gastrointestinal conditions,
They are used as a positive contrast agent in X-ray
examination. Bismuth trioxide
is used in the production of superconductors and electronic
components. Relatively environment-friendly Bismuth trioxide is substituting for
toxic lead oxide in the production of glass, ceramics, fireworks
and batteries. There is an advantage that bismuth trioxide lowers the processing temperature
of ceramics. |
