Magnesium oxide adopts a rock salt structure with a density of approximately 3.58 g/cm³.Based on this information, calculate an estimate of the unit cell edge length in picometers.

Question

Quizplus · Accepted Answer

The rock salt structure is a face-centered cubic lattice. The formula for density is ρ = (Z * M) / (a^3 * N_A), where Z is the number of formula units per unit cell (4 for rock salt), M is the molar mass of MgO (40.3 g/mol), a is the edge length in cm, and N_A is Avogadro's number (6.022 x 10^23 mol^-1). Solving for a and converting to pm gives approximately 421 pm.

Magnesium Oxide Adopts a Rock Salt Structure with a Density