Consider the metal cesium, whose atoms are 0.265 nanometers in radius (for metallic bonds) ... the largest of all the elements. What is the length, in nanometers, of the empty space between atoms that reside along <100> directions in a BCC crystal of Cs metal ? Hint: Another way of asking this is: What is the largest diameter sphere that would fit perfectly in the interstitial space between adjacent (but non-touching) atoms that reside along a common cube edge in BCC cesium metal ?