sodium and potassium carbonate and sulfate are the only ones in their respective anions group that can melt. However, both carbonate CO3 2- and sulfate SO4 2- cannot be discharged. Then, if i want to get pure sodium from sodium carbonate or sulfate how will i attain them? Do i have to increase the electrical energy to a large amount to allow the reaction to occur? then what if i have a small current only, will the circuit be able to conduct electricity and will the polyatomic ions get discharged? if i cannot my pure metal this way, then what should i do to get them? thanks for the help!