For metallic structures, does the packing efficiency (see Sample Exercise 12.1 in textbook) increase or decrease as the number of nearest neighbors (the coordination number) decreases?

We are asked **if the packing efficiency of metallic structures increases or decreases as the number of nearest neighbors (the coordination number) decreases**.

Recall that the **packing efficiency** is the fraction of volume in a crystal **structure** that is occupied by constituent particles** (volume of space occupied by the spheres/total volume)**.

This means that: