B Gallium not becoming a solid again?

[gary0318]

Hi. I am hoping someone can explain to me, what is happening. I have a 100g of 99.99% pure gallium. I placed it in a bowl and sat it in a dehydrator (lower heat than an oven) and set it for 150 degrees. In about 20 minutes, the gallium became liquid. I placed the bowl in the refrigerator and checked on it 20 minutes later and it was still mostly liquid. I than thought that perhaps I would pour water in the bowl (not sure why, LOL). It has been 12 hours and it is still in a liquid form. I am seriously confused.

Any feedback?

Thanks, in advance.

Gary

 

[hilbert2]

Liquids can sometimes get "supercooled", which means that they cool down below their melting point without solidifying, getting stuck in a nonequilibrium thermodynamical state. You can try to scrape the bottom of the bowl with some sharp object to try to initiate the solidifying process.

 

[mfb]

Looks like gallium often gets supercooled. If you still have some solid gallium left, cool your liquid and put the solid crystal in, that should crystallize the rest. Otherwise cool it as much as possible and try to shake it or otherwise induce pressure differences to get some initial seed crystal.

I'm not sure what the water will do, but I would try to remove it.

According to some google results, Zinc oxide has a lattice constant very similar to gallium. Maybe an exotic approach, but if you have a bit of ZnO you could try to bring it into contact with a small amount of gallium.

 

[gary0318]

Thanks. That did the trick. I have another issue though that my wife is not happy about. I used one of her white ceramic dishes to do this experiment. I didn't think that there would be a residual gray cast to the plate afterwards. I have heated it several times and tried a variety of wet papertowels (warm) and then just using a dry sponge at cooler room temperatures. I have managed to get most of it off. But, man. I really though the whole thing would just pour off when it was in liquid state.

 

[mfb]

That did the trick.

What exactly worked?

Don't use things used in chemistry experiments for food afterwards.

 

[gary0318]

Tapping some leftover solid into the liquid form. The first time I tried this, it was like magic. It just went completely solid. Unbelievable! On subsequent experiments, I would have to tap the liquid surface area about every couple centimeters, for about 5 minutes to get a 5" petri dish to go back to solid.