Copper Borate Synthesis and Reactions

Not long ago, I was exploring when I stumbled apon a strange compound known as copper (ii) borate. I know that some of you here have tried to make it and could not figure it out because of problems with the low acidity of boric acid and such. I originally thought that I had made it when I neutralized a solution of boric acid with sodium carbonate and further reacted the sodium tetraborate I had made with copper sulfate. What resulted looked exactly like copper carbonate. I heated it over a burner and became excited when it didnt decompose and turn green. I know know that what I made was copper carbonate and a bit of copper borate and some other junk which kept the copper carbonate from decomposing. The green color eventually became blue again.
A bit later, however, I tryed again with an excess solution of copper sulfate with store bought borax and succeded this time. I ended up with a dark blue/green precipitate with a crystaline look. Some of that was because of extra copper sulfate but after washing with distilled water a bit of it went away.
Anyways, i took a piece of the copper borate and mixed it with a concentrated solution of sodium hydroxide. What resulted was a precipitate of copper oxide and the most being purple solution ive ever seen. Does anyone know what that could be?

Quote: Originally posted by Abromination

Not long ago, I was exploring when I stumbled apon a strange compound known as copper (ii) borate. I know that some of you here have tried to make it and could not figure it out because of problems with the low acidity of boric acid and such. I originally thought that I had made it when I neutralized a solution of boric acid with sodium carbonate and further reacted the sodium tetraborate I had made with copper sulfate. What resulted looked exactly like copper carbonate. I heated it over a burner and became excited when it didnt decompose and turn green. I know know that what I made was copper carbonate and a bit of copper borate and some other junk which kept the copper carbonate from decomposing. The green color eventually became blue again. A bit later, however, I tryed again with an excess solution of copper sulfate with store bought borax and succeded this time. I ended up with a dark blue/green precipitate with a crystaline look. Some of that was because of extra copper sulfate but after washing with distilled water a bit of it went away. Anyways, i took a piece of the copper borate and mixed it with a concentrated solution of sodium hydroxide. What resulted was a precipitate of copper oxide and the most being purple solution ive ever seen. Does anyone know what that could be?

You are going to spill the contents of beaker in the picture.


Here is some borate stuff. You should read that thread.
http://www.sciencemadness.org/talk/viewthread.php?tid=16452

[Edited on 11-7-2018 by TheMrbunGee]

I used about a 70% concentration of NaOH. The precipitate I rinsed and dryed is definatly copper oxide. Ill have to try with different concentrations of sodium hydroxide and maybe add more NaOH to my purple solution. Ill also dry out the solution and see what I end up with, just got to wait for my new hot plate to arrive. Ill attach a picture of my copper borate. The green part of the green/blue doesn't show up well on camera, just picture it with a bit more green.

Well I tried to redo the reaction just like before and it is kind of working. The precipitate right now looks a bit lighter than it should and the textures a bit off but I'm going to try and leave it over night and check again tomorrow. I suspect that not all of the borax has reacted yet, but time and stirring should solve that.

You apparently need to add a large excess of copper sulfate. The reason it looks like copper carbonate is because of unreacted borax. I guess im just a bad chemist