Aluminum / bromine reaction: lighting fuse not necessary; just get away!

Let’s say you don’t want to do the thermite reaction, but you still want to see some very neat looking violent chemistry. The reaction between aluminum and bromine might fit the bill.

2Al(s) + 3Br2(l) –> 2AlBr3(s)

It’s a very simple reaction, but it’s also very exothermic, and can put on an impressive show. Not only is enough heat generated to melt the aluminum metal, but the heat also vaporizes some bromine, producing huge clouds of white and orange smoke. For obvious reasons, this reaction should be done where you’ve got very good ventilation. I used my hood for these pictures and this video.

Here’s a still image of the reaction vessel containing only liquid bromine.

[Liquid bromine in a beaker]
Liquid bromine and its vapor.

Bromine is the dark red liquid at the bottom. Bromine is quite volatile, and you can see orange bromine vapor in the top of the beaker.

About ten seconds after adding some torn aluminum foil, things look more like this.

[Aluminum bromide reaction]
Reaction!

A little later …

[More reaction]
Things begin to heat up! (Click to enlarge)

Oh yeah!

[FIRE!]
Now we’re cooking! (Click to enlarge)

Want to see the video? Here are a few links to a 30-second video file with audio:

The aftermath of the reaction is interesting. Some of the aluminum foil melted and fused with the bottom of the beaker.

[Aluminum burned to a beaker]
Aluminum fused to the beaker

Needless to say, we won’t be using this beaker again.

You can see the aluminum bromide product on the sides of the beaker.

[Aluminum bromide]
Aluminum bromide (white / yellowish solid) on the beaker

The aluminum bromide formed will react with water, causing the release of hydrogen bromide (very nasty to breathe – acidic vapor), so you need to be careful disposing of the product! That reaction is also very exothermic, so touching the product or adding water to it is not recommended. Leave it out long enough, though, and it will absorb water from the air on its own.

Ain’t science neat?

Disclaimer: Do not try this reaction at home. In fact, do not try this reaction at all! You were warned.

Updated with more pictures and video: 04/25/2006

Comments are closed.