When copper and zinc are mixed together with citrate (a natural acid), they form a special combined structure that holds together much better than when either metal is alone with citrate. This teamwork between the metals creates a stronger, more stable complex.

Copper sticks to citric acid much tighter than zinc does, like a stronger magnet holding on better, when you test them the same way.

When you add more salt to a mix of certain chemicals (citrate and metals), it makes them stick together less tightly, just like a science rule says should happen.