Continuing my experimentation with bismuth

[BetaZeta2016]

The more i study this strange element, the more interesting it becomes.

I found that bismuth only shows it's colorful oxides when exposed to air while hot/molten.

I decided to go outside and polish the sample using an abrasive liquid known in Brazil as "Saponáceo Cremoso".
Don't know what it's called in english-speaking countries.

Edit: It's called "Scouring cream" in english.

Anyway, it's used to polish aluminum cookware as well as any other metal surfaces.

So i took my bismuth sample out and started polishing.

The metal finally showed it's natural appearance: A lustrous, shiny and silvery material that resembles lead or iron.

But something more happened: It didn't oxidize. Even after being exposed to air, water or even the oils from my hand, it's still shiny, without any noticeable color change.

But when molten, it tarnishes instantaneously!

Anyone knows why?

 

[Borek]

https://en.wikipedia.org/wiki/Chemical_kinetics#Temperature

 

[BetaZeta2016]

https://en.wikipedia.org/wiki/Chemical_kinetics#Temperature

Very cool. So the heat acts as a catalyst here.

I only hope the metal preserves it's luster for a long time.

 

[Borek]

So the heat acts as a catalyst here.

No. Catalyst is a catalyst, heat is a heat. Both speed up the reaction, but for completely different reasons.

 

[BetaZeta2016]

No. Catalyst is a catalyst, heat is a heat. Both speed up the reaction, but for completely different reasons.

Oh, nice. Thank you for clarifying .

 

[DrDu]

As you were melting Bismuth and already messing up one pan: Did you observe the solid bismuth to float on the melt? Bismuth is one of the few substances (like water) where the solid is less dense than the melt.

 

[BetaZeta2016]

As you were melting Bismuth and already messing up one pan: Did you observe the solid bismuth to float on the melt? Bismuth is one of the few substances (like water) where the solid is less dense than the melt.

Yes, i did!
While the bismuth was molten, there was a small chunk floating on the top of the liquid.

I won't do it on the kitchen again. One pan just went to the trash because of this hehe.

 

[DrDu]

Bismuth is also a relatively strongly diamagnetic substance, i.e. it gets repelled by a magnetic field. If you mount your probe on a string and bring a strong magnet close (best one of these small neodymium magnets) it will turn away.

 

[BetaZeta2016]

Cool experiment too! I tried it with some magnets from old hard drives.

Bismuth diamagnetism is very weak.
But still stronger than any other material i have ever seen.