To understand the equilibrium spacing in a crystalline solid, we need to consider the concepts of net inter-atomic force and potential energy:
Now, let's evaluate the given options:
Therefore, the correct answer is that at equilibrium spacing in a crystalline solid, the net inter-atomic force is zero, and the potential energy is at its minimum.
| Column I | Column II |
|---|---|
| (P) Tetragonal | (1) $a \neq b \neq c$, $\alpha = \beta = \gamma = 90^\circ$ |
| (Q) Rhombohedral | (2) $a = b \neq c$, $\alpha = \beta = \gamma = 90^\circ$ |
| (R) Orthorhombic | (3) $a \neq b \neq c$, $\alpha = \gamma = 90^\circ \neq \beta$ |
| (S) Monoclinic | (4) $a = b = c$, $\alpha = \beta = \gamma \neq 90^\circ$ |
The lattice parameter of face-centered cubic iron ($\gamma$-Fe) is 0.3571 nm. The radius (in nm) of the octahedral void in $\gamma$-Fe is _______________