Bismuth trioxide is a dense yellow solid that is used as a non-toxic alternative to lead oxides in pyrotechnic mixes.
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.
A yellow solid that can appear with a slight green tinge in impure samples, Bi2O3 is remarkably dense.
Pyrotechnic supplies will most likely sell Bi2O3. It has no shipping restrictions, so pyrotechnic grade oxide can be found online reasonably priced.
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.
- Dragon's eggs
- Explosive thermite
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.