Bismuth
post transition metalProperties
| Property | Value |
|---|---|
| Atomic Mass | 208.98 amu |
| Category | post transition metal |
| Group | 15 |
| Period | 6 |
| Electron Configuration | [Xe] 4f14 5d10 6s2 6p3 |
| Electronegativity | 2.02 (Pauling) |
| Oxidation States | 5, 3, -3 |
| Melting Point | 544.7 K (271.6 °C) |
| Boiling Point | 1837 K (1563.8 °C) |
| Density | 9.78 g/cm³ |
| Discovered By | Claude Geoffroy the Younger (1753) |
About Bismuth
Bismuth is the cheat code of the heavy metals. Sitting next to lead and polonium on the periodic table, it has none of their toxicity profile — bismuth subsalicylate is the active ingredient in Pepto-Bismol, and you swallow it by the spoonful. For nearly a century chemists called Bi-209 the heaviest stable nuclide; in 2003 a French group at the Laboratoire Souterrain de Modane finally caught it alpha-decaying with a half-life of 1.9 × 10¹⁹ years, which for any laboratory purpose is indistinguishable from stable. The metal itself behaves oddly enough to be memorable: it expands about 3% on freezing (only water, gallium, and a handful of others do this), it is the most diamagnetic metal known, and it has the lowest thermal conductivity of any metal except mercury. Slow-cooled bismuth grows hopper crystals with iridescent oxide films, the kind you see on every periodic-table poster. In the lab it shows up as a green-chemistry replacement for lead in low-melting Wood's-metal-style alloys and for tetraethyl lead in shotgun pellets.
Fun Fact
Bismuth-209 has the longest measured half-life of any radioactive isotope — about 19 quintillion years, roughly a billion times the current age of the universe.
Common Uses
- Active ingredient (bismuth subsalicylate) in Pepto-Bismol
- Lead-free shot and fishing sinkers as a non-toxic alternative
- Low-melting fusible alloys for fire-sprinkler triggers and Wood's metal
- Bismuth oxychloride pearlescent pigment in cosmetics
- Bismuth telluride thermoelectric Peltier cooling modules