This observation led to the concept of transport number, the fraction of the electric current carried by each ionic species.

Non-charged, higher molecular weight, and less mobile ionic species will not typically be significantly removed.

The following oxidation/reduction tree of an ionic species shows the various ways that a substance can be broken down.

Some ionic species can pass through the barrier while others cannot.

In such cases, the condensed formula only need be complex enough to show at least one of each ionic species.

The current generated by ion pumps is dependent on the ionic species specific to that pump.

The maintenance of these concentration gradients requires active transport of ionic species.

The analysis of physisorption for polar or ionic species is more complex.

It is a molecular species, not ionic, consistent with its low boiling point.

The propagation mechanisms appear to involve both ionic and radical species.