Bismuth

From Wikinfo

General Name, Symbol, Number Bismuth, Bi, 83 Chemical series Poor metals Group, Period, Block 15 (VA), 6 , p Density, Hardness 9780 kg/m3, 2.25 Appearance lustrous reddish white Atomic Properties Atomic weight 208.98038 amu Atomic radius (calc.) 160 (143) pm Covalent radius 146 pm van der Waals radius no data Electron configuration [Xe]4f14 5d10 6s2 6p3 e- 's per energy level 2, 8, 18, 32, 18, 5 Oxidation states (Oxide) 3, 5 (mildly acidic) Crystal structure Rhombohedral Physical Properties State of matter Solid Melting point 544.4 K (520.3 °F) Boiling point 1837 K (2847 °F) Molar volume 21.31 ×10-3 m3/mol Heat of vaporization 104.8 kJ/mol Heat of fusion 11.3 kJ/mol Vapor pressure 0.000627 Pa at 544 K Speed of sound 1790 m/s at 293.15 K Miscellaneous Electronegativity 2.02 (Pauling scale) Specific heat capacity 122 J/(kg×K) Electrical conductivity 0.867 106/m ohm Thermal conductivity 07.87 W/(m×K) 1st ionization potential 703 kJ/mol 2nd ionization potential 1610 kJ/mol 3rd ionization potential 2466 kJ/mol 4th ionization potential 4370 kJ/mol 5th ionization potential 5400 kJ/mol 6th ionization potential 8520 kJ/mol Most Stable Isotopes iso NA half-life DM DE MeV DP 207Bi {syn.} 31.55 y Epsilon 2.399 207Pb 208Bi {syn.} 3,368,000 y Epsilon 2.880 208Pb 209Bi 100% (1.9±0.2) ×1019y Alpha   205 Tl SI units & STP are used except where noted.

Bismuth is a chemical element in the periodic table that has the symbol Bi and atomic number 83. This is heavy, brittle, white crystalline trivalent poor metal that has a pink tinge and chemically resembles arsenic and antimony. Most diamagnetic of all metals, bismuth has the lowest thermal conductivity of all the elements except mercury. Lead-free bismuth compounds are used in cosmetics and in medical procedures.

Contents 1 Notable Characteristics 2 Applications 3 History 4 Occurrence 5 External Links 5.1 References

Notable Characteristics

Before 2003, Bismuth was thought to be the heaviest stable element, however research at the Institut d'Astrophysique Spatiale in Orsay, France measured the alpha emission half-life of the metal to be (1.9 +/- 0.2) × 10¹⁹ years (meaning it is not a stable element). It is a brittle metal with a pinkish hue with an iridescent tarnish. Among the heavy metals, it is the heaviest and the only non-toxic. No other metal is more diamagnetic than bismuth, except mercury. This metal, which occurs in its native form, has a high electrical resistance and also has the highest Hall effect of any metal (that is, it has the greatest increase in electrical resistance when it is placed in a magnetic field). When heated in air bismuth burns with a blue flame and its oxide forms yellow fumes.

Applications

Bismuth oxychloride is extensively used in cosmetics and bismuth subnitrate and subcarbonate are used in medicine. Other uses; "Bismanol" (MnBi) is a strong permanent magnet.

• Bismuth alloys have low-melting temperature and are widely used for fire detection and suppression system safety devices.
• Bismuth is used in producing malleable irons and is finding use as a catalyst for making acrylic fibers.
• Also used as a thermocouple material.
• A carrier for U-235 or U233 fuel in nuclear reactors.
• Bismuth has also been used in solders.

In the early 1990s, research began on the evaluation of bismuth as a nontoxic replacement for lead in such uses as ceramic glazes, fishing sinkers, food processing equipment, free-machining brasses for plumbing applications, lubricating greases, and shot for waterfowl hunting.

History

Bismuth (German Weisse Masse meaning "white mass"; later Wisuth and Bisemutum) was confused in early times with tin and lead due to its resemblance to those elements. In 1753 Claude Geoffroy Junine showed that this metal is distinct from lead.

Occurrence

Bismuthinite and bismite are the most important ores of bismuth. Canada, Bolivia, Japan, Mexico, and Peru are major producers. Bismuth produced in the United States is obtained as a by-product of copper, gold, lead, silver, tin and especially lead ore processing. The average price for bismuth in 2000 was US$ 3.50 per pound.

External Links

• WebElements.com - Bismuth
• EnvironmentalChemistry.com - Bismuth
• Bismuth breaks half-life record for alpha decay

References

• Adapted from the Wikipedia article, "Bismuth" http://en.wikipedia.org/wiki/Bismuth, used under the GNU Free Documentation License