_thisnameistaken
Harmless
Posts: 4
Registered: 16-8-2022
Member Is Offline
|
|
an annoying copper complex
i have a tetraamine copper sulfate complex im trying to get crystals from, but it seems impossible to precipitate! ive used every last drop of ethanol
(which was supposed to help it crash out, but i guess i either have too little or the procedure was wack), cooled it down under careful watch to lower
solubility, and done countless vacuum filtrations to get something out, but all has failed. And i cant even try to concentrate it since it would just
make copper hydroxide. any suggestions?
|
|
|
Sulaiman
International Hazard
Posts: 3695
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
GUESS : Anhydrous magnesium sulphate added until some precipitate appears?
Edit: even better... anhydrous copper sulphate... less likely to modify your product.
[Edited on 2-9-2022 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Romix
Hazard to Others (Literally)
Posts: 483
Registered: 19-6-2015
Member Is Offline
Mood: No Mood
|
|
Once I concentrated copper ammonia hydroxide complex to very high concertation it was dark black, when I poured the solution out I found a lot of
crystals growing at the bottom of the HDPE milk bottle used.
|
|
|
Romix
Hazard to Others (Literally)
Posts: 483
Registered: 19-6-2015
Member Is Offline
Mood: No Mood
|
|
Concentrated it by freezing and pouring out many many times.
[Edited on 2-9-2022 by Romix]
|
|
|
vano
National Hazard
Posts: 661
Registered: 22-3-2019
Location: Georgia
Member Is Offline
|
|
I never grow this complex compound crystal, but for soluble amino complexes im using isopropyl alcohol, powder precipitates very easily, after plus
few hours in the freezer.
|
|
|
Amos
International Hazard
Posts: 1406
Registered: 25-3-2014
Location: Yes
Member Is Offline
Mood: No
|
|
Contrary to a lot of internet pages, you can actually boil or evaporate this complex to concentrate it; you lose some ammonia but not that much.
Additionally, acetone and isopropanol are much better at precipitating it. The most important thing for getting a smooth result is using as
concentrated solutions of ammonia and copper sulfate as possible. With super dilute ammonia you can maybe use powdered, solid copper sulfate and grind
it in a mortar as you add the ammonia, eventually getting it all to dissolve.
|
|
|
_thisnameistaken
Harmless
Posts: 4
Registered: 16-8-2022
Member Is Offline
|
|
Quote: Originally posted by Amos  | | Contrary to a lot of internet pages, you can actually boil or evaporate this complex to concentrate it; you lose some ammonia but not that much
|
sadly not, most of the solution turned to hydroxides and oxides and some nasty ammonia vapor started coming
out when i did so
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
