|
|
Atomic Number: |
83 |
Melting Point: | 271.4 ºC | |
| Atomic Symbol: | Bi | Boiling Point: | 1564 ºC | ||
| Atomic Weight: | 208.9804 amu | Density: | 9780
kg/m 3 |
||
| Atomic Radius: |
155 pm |
Oxidation States: | 5, 3 | ||
| Covalent Radius: | 146 pm | Electron Configuration: | [Xe]6s24f145d106p3 | ||
| van der Waals Radius: |
-- |
State of Matter: | solid |
(Ger. Weisse Masse, white mass; later Wisuth and Bisemutum) In early times bismuth was confused with tin and lead. Claude Geoffroy the Younger showed it to be distinct from lead in 1753.
It is a white, crystalline, brittle metal with a pinkish tinge. It occurs in a native state. Bismuth is the most diamagnetic of all metals, and the thermal conductivity is lower than any metal, except mercury. It has a high electrical resistance, and has the highest Hall effect of any metal (i.e., greatest increase in electrical resistance when placed in a magnetic field). High-purity bismuth can form into distinctive hopper crystals. These colorful laboratory creations are typically sold to hobbyists.
The most important ores are bismuthinite or bismuth glance and bismite. Peru, Japan, Mexico, Bolivia, and Canada are major bismuth producers. Much of the bismuth produced in the U.S. is obtained as a by-product in refining lead, copper, tin, silver, and gold ores.
"Bismanol" is a permanent magnet of high coercive force, made of MnBi, by the U.S. Naval Surface Weapons Center. Bismuth expands 3.32% on solidification. This property makes bismuth alloys particularly suited to the making of sharp castings of objects subject to damage by high temperatures. With other metals such as tin, cadmium, etc., bismuth forms low-melting alloys which are extensively used for safety devices in fire detection and extinguishing systems. Bismuth is used in producing malleable irons and is finding use as a catalyst for making acrylic fibers. When bismuth is heated in air it burns with a blue flame, forming yellow fumes of the oxide. The metal is also used as a thermocoupling material, and has found application as a carrier for 235U or 233U fuel in nuclear reactors. Its soluble salts are characterized by forming unsoluble basic salts on the addition of water, a property sometimes used in detection work. Bismuth oxychloride is used extensively in cosmetics. Bismuth subnitrate and subcarbonate are used in medicine. It is finding use as a catalyst for making acrylic fibers. Bismuth has also been used in solders due to fact that it expands slightly upon freezing.
Before 2003, bismuth was thought to be the heaviest stable element. However, researchers at a French institute measured the alpha emission half-life of Bi-209 to be 1 E19 s and more (1.9 ± 0.2) × 1019 years, meaning that bismuth is not stable after all.
Bismuth and its salts can cause kidney damage, although the degree of such damage is usually mild. Large doses can be fatal. Industrially it is considered one of the less toxic of the heavy metals. Serious and sometimes fatal poisoning may occur from the injection of large doses into closed cavities and from extensive application to burns. It is stated that the administration of bismuth should be stopped when gingivitis appears, for otherwise serious ulceration stomatitis is likely to result. Other toxic results may develop, such as a vague feeling of bodily discomfort, presence of albumin or other protein substance in the urine, diarrhea, skin reactions and sometimes serious exodermatitis.
