Question

What is the difference between `"formula unit"` and `"empirical formula"`?

Answer 1

A `"formula unit"` is in effect the `"empirical formula"`, and it is particularly used to describe non-molecular species.

Explanation:

And the `"empirical formula"` is the simplest whole number ratio that describes consitiuent atoms in a species.

Typically, we use `"formula unit"` when we describe the composition of non-molecular entities such as salts. Common salt, sodium chloride, is certainly not molecular. Its description by its formula unit as `NaCl` is unambiguous.