# Out of CaCO3 and MgCO3, which has higher electrical conductivity of molten solution? [closed]

According to me, Mg will be more hydrated and so should have lesser conductivity. Is that correct?

• The 'hydration' makes this question very unclear. – Jon Custer Sep 5 '19 at 13:31
• This question needs to be fixed: neither carbonate is soluble in water and neither melts without decomposition to the respective oxide. If the question is about transport coefficients or whatever, it should ask that. Otherwise, the question should be on hold or closed. – Ed V Sep 5 '19 at 13:41
• "Molten solution" is a contradiction in terms. – Ivan Neretin Sep 5 '19 at 13:53
• @EdV - but they do melt, just not at STP in air. For example geochemicalperspectivesletters.org/documents/GPL1813_noSI.pdf - Properties of molten CaCO3 at high pressure - important in earth sciences. – Jon Custer Sep 5 '19 at 14:23
• @JonCuster Quite honestly, do you really think this is what the question is about? The OP should replace this with a well-formed question and title. Otherwise, it is just leading to non-productive mind reading. – Ed V Sep 5 '19 at 14:30

"Molten" here probably means "liquid". While the carbonates gave too little solubility to be considered for electrolyte, we can compare the conductances of $$\ce{Ca^{2+}}$$ and $$\ce{Mg^{2+}}$$ in dilute solution. In this reference from the USGS, conductances from various common ions are given and, indeed, calcium ion has a greater conductance than magnesium ion in solution. But the difference amounts to only a few percent for the overall conductivity of a chloride salt solution at a given concentration.