Difference between revisions of "Bismuth"
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Revision as of 02:26, 14 June 2015
Bismuth is a chemical element with symbol Bi and atomic number 83. It is a post-transition metal, grey and dense.
Contents
Properties
Chemical
Bismuth is stable to both dry and moist air at ordinary temperatures. When red-hot, it reacts with water to make bismuth trioxide[1].
- 2 Bi + 3 H2O → Bi2O3 + 3 H2
Bismuth dissolves in concentrated sulfuric acid to make bismuth(III) sulfate and sulfur dioxide.
- 2 Bi + 6 H2SO4 → 6 H2O + Bi2(SO4)3 + 3 SO2
Bismuth reacts with halogens to produce bismuth halides. Unlike bismuth trifluoride and bismuth triiodide, bismuth trichloride and bismuth pentafluoride rapidly hydrolyse in moist air and water. Bismuth will react with most acids, but oxygen or hydrogen peroxide has to be present to oxidize the metal.
Physical
Bismuth is a brittle white-silver metal in its pure form. It will oxidize in air to form an iridescent hue, under certain circumstances, showing many colors from yellow to blue. It has the lowest thermal conductivity of all known metals and it is the most diamagnetic pure element. Similar to antimony, gallium, germanium and silicon, bismuth is denser in the liquid phase than the solid (like ice), expanding 3.32% on solidification.
Availability
Bismuth is present as bismuth subsalicylate in Pepto-Bismol. It can be extracted from the compound, as shown here.
Large chunks of metal can be bought as Hopper crystals, that display beautiful iridescence.
Bismuth is found in certain electronics, mostly as lead-free solder. The solder that binds the ceramic lid to the CPU appears to be mostly of bismuth, as after melting it and letting it cool in open air it displays the typical iridescence.
Preparation
Bismuth can be extracted from Pepto-Bismol, by adding acid and then reducing the metal with either aluminium or other reducing metal.
Projects
- Making bismuth crystals
- Levitation with magnets
Safety
Unlike it's surrounding metals (lead, antimony, polonium), bismuth and bismuth compounds have low toxicity. Overexposure to bismuth, however, can result in the formation of a black deposit on the gums, known as a bismuth line.
Some of its compounds, such as bismuth chloride will hydrolyze in moist air and is corrosive to skin, so protection is required when handling the compound.
