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If $H_2O$ ions have a net electric charge and electric current is the flow of electric charge, can a stream of water ions be considered an electric current? If so, is it conceivably possible (not necessarily feasible) to use a flow of water ions in place of a copper wire carrying an electrical current in an electrical circuit? For example, in a bizarre Rube Goldberg contraption sort of situation.

Edit: I guess this question applies to any sort of ion in either gas or liquid state. I don't know enough chemistry to know if $H_2O$ ions are even a thing that exist in the real world

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  • $\begingroup$ Thanks for the answers, they were all helpful and I wish I could accept each of them $\endgroup$ – nonex Oct 17 '14 at 17:05
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Yes, electric current is movement of any kind of charges.

The problem with your particular example is that most liquids containing ions are also conductive. Electrons will hop between molecules and equalize the ionic charges, then end up providing most of the conduction themselves.

There are cases where actual ion migration results in much of the current, such as in a battery. This process is also used in reverse in electro-plating applications.

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  • $\begingroup$ Thanks. Are there any examples of an ionic gas being used as an electric current? I'm sure it's in no way practical, I'm just curious. $\endgroup$ – nonex Oct 17 '14 at 17:06
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    $\begingroup$ @nonex: Ionic doesn't mean net charge. In fact, most things that are composed of charged ions have them in roughly equal opposite numbers. If they didn't, a net charge would build up, which would create a force that would migrate the imballanced ions back to equillibrium. $\endgroup$ – Olin Lathrop Oct 17 '14 at 17:29
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Well, technically yes (assuming you mean ionized and not just "charged"). Current (in simple terms) is only the time rate of charge flow, which is not exclusively limited to electrons or any specific charge carrier. Electrolytic conductivity is well documented, naturally being higher for strong electrolytes as compared to the ones that dissociate weakly in the solvent. It certainly does happen biologically too, in ion channels. However, more massive species are less mobile in general, so when one has a choice, it is better to go with lighter species (like electrons) doing the honours!

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