Bismuth trioxide

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Bismuth trioxide
Names
IUPAC names
Bismuth(III) oxide
Bismuth trioxide
Other names
Bismite
Bismuth sesquioxide
Bismuth trioxide
Bismuth Yellow
Dibismuth trioxide
Properties
Bi2O3
Molar mass 465.96 g/mol
Appearance Yellow solid
Odor Odorless
Density 8.90 g/cm3
Melting point 817 °C (1,503 °F; 1,090 K)
Boiling point 1,890 °C (3,430 °F; 2,160 K)
Insoluble
Solubility Dissolves in acids
Vapor pressure ~0 mmHg
Thermochemistry
-271.6 J·mol-1·K-1
-578 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Antimony(III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Bismuth trioxide is a dense yellow solid that is used as a non-toxic alternative to lead oxides in pyrotechnic mixes.

Properties

Chemical

Like other oxides, on addition to an acid the bismuth salt and water are formed. It is therefore a useful stating point in creating bismuth compounds such as bismuth nitrate.

A bismuthate ion exists and it is a very powerful oxidiser, able to oxidise chromates and manganates. It can be produced from bismuth trioxide by heating with a molten alkali hydroxide.

It's reaction with magnesium and aluminium powders is exceptionally violent for a thermite, and will explode due to the density of the oxide and the low reactivity of bismuth. Therefore this is not a viable way of producing the metal from the oxide as any metal produced is vaporised.

Mixes of magnesium and bismuth trioxide are labelled 'Dragon's Eggs', where pellets are designed to explode after a short period of burning.

Molten bismuth oxide is an extremely powerful oxidizer that can dissolve platinum.

Physical

A yellow solid that can appear with a slight green tinge in impure samples, Bi2O3 is remarkably dense.

Availability

Pyrotechnic supplies will most likely sell Bi2O3. It has no shipping restrictions, so pyrotechnic grade oxide can be found online reasonably priced.

Preparation

Burning bismuth metal by a blow torch is an uncontrolled way to make Bi2O3, and much of it escapes if there is not a good method of catching it as it is created.

Projects

  • Dragon's eggs
  • Explosive thermite

Safety

Bismuth is comparatively a lot less toxic than lead, but it is still inadvisable to breathe in metal vapours or large amounts of metal oxides.

References

Relevant Sciencemadness threads