What causes my copper sulfate and sodium carbonate mix to gel rather than solid?

[JonathanT]

I’m trying to precipitate copper carbonate from a solution of copper sulfate and sodium carbonate, but my product keeps coming out as more of a blue gel than a solid powder. I followed the procedure for a double displacement reaction, but I’m wondering if the temperature or the concentration of my reactants is causing this consistency issue.

[MichaelVR]

That blue gel sounds like what you get when copper carbonate precipitate forms as a hydrated or basic carbonate. In my experience, if the solution is a bit concentrated, the solid comes out as a blue gel rather than a crisp powder.

[JonathanWW]

Temperature did weird things in my tiny experiments too. At room temp I got a soft, gel-like mass; when it cooled and aged, I saw some small grains but it never fully dried into powder.

[John57]

Concentration and rate of mixing matter more than you’d think. I found that very concentrated copper sulfate with carbonate led to a sluggish mushy precipitate that stuck to glass.

[Ryan.J]

Could the issue be that you’re forming a basic or hydrated copper-containing solid rather than the expected precipitate?