NaCl and KF have the same crystal structure. The only difference between the two is the distance that separates cations and anions. (b) Use the ionic radii given in Figure 7.8 to estimate the Na─Cl and K─F distances.

Key Concepts

Ionic Radii

Ionic radii refer to the effective size of an ion in a crystal lattice, which is influenced by its charge and the surrounding ions. Cations are typically smaller than their neutral atoms due to the loss of electrons, while anions are larger due to the gain of electrons. Understanding ionic radii is crucial for estimating distances between ions in ionic compounds.

Crystal Structure

Crystal structure describes the orderly arrangement of ions in a solid, which determines the properties of the material. In the case of NaCl and KF, both adopt a face-centered cubic lattice structure, where each ion is surrounded by six oppositely charged ions. This arrangement is essential for understanding how ionic distances are calculated based on the positions of cations and anions.

Ionic Bonding

Ionic bonding occurs when electrons are transferred from one atom to another, resulting in the formation of positively charged cations and negatively charged anions. The electrostatic attraction between these oppositely charged ions leads to the formation of ionic compounds like NaCl and KF. This concept is fundamental for understanding the interactions that dictate the distances between ions in a crystal lattice.