whats this solid forming in my experoment?

[Ice_Phoenix87]

hey, i just tried to make copper sulfate by electrolysising it in a solution of vinegar and epsom salt. on the copper it is forming a black solid. it is soft. But the good thing is the solution is turning blue . i will crystalize it tomorrow.

[YT2095]

it sounds like copper oxide.

 

Edit: it MAY form a hydroxide eventualy though.