The samples are also required to be salt-free; they should not contain ions.

However, rain water (depending on how you get to it) can contain ions, or trace organic compounds.

Most rocks, minerals, and things made from minerals contain ions.

Sometimes small carbon containing ions are included in such schemes.

Some cage structures that contain other ions are known.

In between these electrodes is the electrolyte, which contains ions that can freely move.

Rainwater and distilled water are soft, because they also contain few ions.

However, such secretions also contain important ions which are essential for the normal functioning of the body.

Tom explained that the colored gas used for the "sky paint" contained ions of Inertite.

Many of these are electrolytes, since they contain solute ions, such as potassium.