Sciencemadness Discussion Board

Jelly aluminium+3 substance

Romix - 19-10-2015 at 04:29

I displaced Bi and Cu chlorides with aluminium.
Evaparated, light green solution, wonted to crystallize it.
I think it's light green because of nickel impurities in it, maybe others too.

But it formed jelly substance, not crystals.
Almost insouble at room temp, when heated it melts. Melting point of it ~ 70 - 80°C. And goes into jelly state again on cooling.

Do you know what it can be?

Last time I crystalised yellow crystalls of AlCl3, reacting Al directly with acid.
They decompose on heating. There wos no decomposition with jelly substance, as distillate in reciever not acidic.




[Edited on 19-10-2015 by Romix]

[Edited on 19-10-2015 by Romix]

blogfast25 - 19-10-2015 at 06:43

Quote: Originally posted by Romix  

But it formed jelly substance, not crystals.
Almost insouble at room temp, when heated it melts. Melting point of it ~ 70 - 80°C. And goes into jelly state again on cooling.

Do you know what it can be?

Last time I crystalised yellow crystalls of AlCl3, reacting Al directly with acid.
They decompose on heating. There wos no decomposition with jelly substance, as distillate in reciever not acidic.


What was the pH of the solution? Your jelly is almost certainly Al(OH)3.nH2O.

Romix - 19-10-2015 at 06:56

Quote: Originally posted by blogfast25  
Quote: Originally posted by Romix  

But it formed jelly substance, not crystals.
Almost insouble at room temp, when heated it melts. Melting point of it ~ 70 - 80°C. And goes into jelly state again on cooling.

Do you know what it can be?

Last time I crystalised yellow crystalls of AlCl3, reacting Al directly with acid.
They decompose on heating. There wos no decomposition with jelly substance, as distillate in reciever not acidic.


What was the pH of the solution? Your jelly is almost certainly Al(OH)3.nH2O.


If it's Al(OH)3.nH2O where chlorine anions gone?
And aluminium hydroxides and oxide are white powder.

Romix - 19-10-2015 at 07:00

It went back to jelly state, over night standing at room temp, I added more water, and heated it, dissolved all.
Unsolube at room temp.

blogfast25 - 19-10-2015 at 08:02

Quote: Originally posted by Romix  
It went back to jelly state, over night standing at room temp, I added more water, and heated it, dissolved all.
Unsolube at room temp.
Quote:
If it's Al(OH)3.nH2O where chlorine anions gone?
And aluminium hydroxides and oxide are white powder.


The Cl anions stay in solution.

What you observed could be hydrolysis:

AlCl3 + H2O < === > Al(OH)Cl2 + HCl and:

Al(OH)Cl2 + H2O < === > Al(OH)2Cl + HCl

These aluminohydroxichlorides are jelly like and may re-enter solution in some circumstances.

To avoid aluminohydroxichlorides forming, always keep pH really low.

Freshly prepared aluminium hydroxides is a voluminous, watery jelly, not a powder at all.

[Edited on 19-10-2015 by blogfast25]

Romix - 19-10-2015 at 11:34

Quote: Originally posted by blogfast25  
Quote: Originally posted by Romix  
It went back to jelly state, over night standing at room temp, I added more water, and heated it, dissolved all.
Unsolube at room temp.
Quote:
If it's Al(OH)3.nH2O where chlorine anions gone?
And aluminium hydroxides and oxide are white powder.


The Cl anions stay in solution.

What you observed could be hydrolysis:

AlCl3 + H2O < === > Al(OH)Cl2 + HCl and:

Al(OH)Cl2 + H2O < === > Al(OH)2Cl + HCl

These aluminohydroxichlorides are jelly like and may re-enter solution in some circumstances.

To avoid aluminohydroxichlorides forming, always keep pH really low.

Freshly prepared aluminium hydroxides is a voluminous, watery jelly, not a powder at all.

[Edited on 19-10-2015 by blogfast25]


Solid jell. Not solution. And distilate not acidic!

[Edited on 19-10-2015 by Romix]

Romix - 23-10-2015 at 08:16

Left it for a week, checked today, it turned into substance that looks like skimed milk. greenish in colour.
Added more water, and stired, all of it dissolved at room temp.

Romix - 23-10-2015 at 10:09

After 3 hours, cloudy compound begin settling down.
If this is Al(OH)2Cl, why it's dark green.

I let it settle to bottom.
Then try crystalise nickel chloride from solution, and wash this cloudy shit again with water and look for colour change.

Romix - 23-10-2015 at 10:10

Do you know solubility of aluminium compound that you gave formula of?
And ~ at what temp it decomposes?

[Edited on 23-10-2015 by Romix]

[Edited on 23-10-2015 by Romix]

[Edited on 23-10-2015 by Romix]