Why double-click? You could set a hyperlink on the cell with "Salt" that
takes you to the range that explains the details on NaCL.

1. Name the range of details (only one cell needs to be named). This will
be where you are taken.
2. In the cell where you have "Salt", choose INSERT then HYPERLINK; click
on "Place in This Document" on the left; pick your named range and click ok.

Now whenever someone clicks on the Salt cell you are taken to your details
on it.

If you want something more dynamic, you'd have to write a macro that reads
the value of the cell you're double-clicking (or when you click on custom
button in a toolbar) and it does a look up to see where it needs to take you.

"mjb" wrote:

I have set up an inventory of the chemicals we keep on an excel
spreadsheet... What I want to be able to do is to double-click on a chemical
(ie double-click in a cell) and be referred to new cell that lists the
synonym of that chemical.

In other words, when I double- click on 'salt' the spreadsheet moves me to
cell that says 'NaCl'... and thus, all of the pertinent information for NaCl.