How to know which complex ions are colorless?

Anyone know how to capture and store negative ions?

• I want to collect and store negative ions from the air. All suggestions are welcome.

• Answer:

  That's a hard one. One problem would be to collect them and keep them together cause once they come into contact with the container, they will loose their charge and they will become neutralized. If they do not become neutralized, they will repel each other so much that they will not stay together. It would be extremely difficult to get more than a few atoms together. There would be no way of knowing how many they are or exactly where they are. My suggestion would be to use negative ions within a solution such as water + salt. The other would be to charge up a metalic object such as a vandegraf generator positively to about +3000 Volts and then believe that the air around the vandegraf contains negatively charged ions. I am just wondering, what do you intend to do with the negative ions?