Copper carbonate and HCl is fine. But for CuCl2 from CuSO4 with as less contamination as possible I would suggest to dissolve the sulfate in water and to add soda (sodium carbonate) in excess and to boil this solution for some time. First the coppercarbonate will form - a nice fluffy light-blue precipitate which would take days to settle but no need to wait for this to happen as it will turn to black copper oxide upon boiling, this now settles well at the bottom and can be washed free from any water soluble residue with ease as copperoxide is not soluble in water at all. Dried, weighed and an stochiometric amount of HCl added - voila! - CuCl2. (if one uses muriatic acid from poolsupply or hardware stores it is advised to distill this before use or all this tedious getting rid of impurities is in vain - muriatic acid contains heaps of shit, mostly iron - this gets very obvious upon distillation)
moo´s method works - of course - I suggest this alternative way solely as the step through copperoxide bears advantages in removing water soluble salts - what might come advantageous - in my humble opinion, is understood.
