Flexible Crystals?

[YT2095]

I would never have thought it possible if I hadn`t seen it with my own eyes this morning!

 

I`m allowing a saturated soln of Ammonium Nitrate to evaporate under a fan blowing cold air.

there a long (5+ inches) crystals formed in this soln, as eventualy the crystals start to form like frost up the sides of the evap dish, I normaly try to lift the existing crystals up in to the aur for better evap.

as I did so they bent

I can take a long single crystal and slowly bend it into a loop, How is this possible!?

 

I urge anyone with a large enough amount of AN to try this themselves, there`s nothing wasted as when it`s dry you get your AN back.

[bob000555]

There’s probably still some water in them and their forming a paste so thick it looks solid.

[YT2095]

these are crystals, clear as glass and about 3 mm thick.

 

not even Close to pasty as when you bend them too fast they snap.

[woelen]

If you carefully bend them and then release them, do they go back to their original shape, or do they keep their bent shape?

[YT2095]

They maintain their shape perfectly, you have to apply positive pressure but very slowly, it`ll work just fine.

they even dry out in the shape you leave them in

[Skye]

I imagine the lattice is not completely formed, so there are sheets of crystal that are sliding over each other like graphite.

[YT2095]

that sounds a reasonable idea, with the difference that rather than being sheets, this is more like fibers, lots of long thin crystals grouped lateraly to form a seemingly larger Single crystal. they will bend in any direction too, although they will splinter upon a twisting action much easier.

I guess it`s a bit like glass fibers against a solid length of glass, the fibers will be a little more flexible that the solid peice.

 

it really is Strange to see though, very contra-intuitive.

[woelen]

It might also be that the crystals form an intercalation compound, with many water molecules trapped into the lattice. If the amount of trapped water is relatively large, then the crystal lattice can be deformed, with watermolecules moving from one hole to another hole. Because these watermolecules need some space, the crystal then is permanently deformed and does not snap back, when the force is taken away.

 

It is quite an interesting phenomenon though. I have a bag of 25 kilo of KAS fertilizer and I'll see if I can do something like this with that fertilizer (it also contains chalk, magnesia and other insoluble stuff, so I need some filtering).

[YT2095]

yeah, this was NitroChalk I used too, basicly AN with the clayish stuff added, a simple filtering with a drop of sulphuric acid does the trick.

[Neil9327]

Ammonium Nitrate is an explosive isn't it?

 

Isn't there a risk of it blowing up if you crystalize it, and start bending it?

[YT2095]

no risk at all.

secondly it will only explode under certain conditions, 1) it needs a suitable blasting cap to initiate a reaction, 2) it also needs to be of a certain density and critical diameter, 3) it have to be Very Dry (water free).

[woelen]

You really have to put a lot of effort in making ammonium nitrate detonate. The average starter in home chemistry will not be capable of doing that, so indeed, no need to worry about accidental explosion by simply bending the crystals.

 

If it were really a sensitive explosive, then it definitely would not be sold to farmers as a very common fertilizer.

[Bluenoise]

I've noticed the same thing with ammonium nitrate. Some fertilizer that we by contains the crystals. They are very soft and flexible.

 

You may want to try completely drying them out. I doubt 100C in a oven for 30 mins will be anywhere enough to detonate them, but you might want to make sure. That should remove all the water. And I'm sure leave them really dry and hard.

Plus you only need to dry a couple small ones to check anyways.

[YT2095]

I`m one step ahead of you

I have several 5cm+ crystals drying out slowly, some straight and some I bent prior.

its at 50c with a fan on it, the crystals rest on a bag of charged Silica Gel desicant also.

as for 100c in an oven even with a hoge pile it wouldn`t detonate, even hotter it would just decompose into nitrous oxide.

it needs a Shockwave and a suitable density to propogate this wave in order to detonate, even then it would likely be a low order detonation without a suitable sensitiser (unless you have tonne of the stuff).

[akcapr]

Speaking of ammonium nitrate i was watching this tv show and they mixed AN and something else in a flask and the reaction produced N2O- im just curious to what the reaction was if anyone knows

[woelen]

NH4NO3 produces N2O in itself already, when heated carefully:

 

NH4NO3 ---> N2O + 2H2O

 

A small amount of water can be added to make the reaction somewhat safer. It very easily goes out of control, because it needs heating. Did they in the show heat the ammonium nitrate?

 

The N2O, produced in this experiment is not very pure though. It also contains N2, NO and NO2. Because of the latter two impurities, the N2O produced this way is absolutely unsuitable for inhalation or for use in cream.

[akcapr]

i thought they mixed it with something, they bubbled the gas through water i guess to seperate out the NO