Chemistry

The key is connecting density, molar mass, and unit cell volume to find how many formula units fit inside. Use the density formula $\rho = \frac{Z \times M}{N_A \times V_{\text{cell}}}$, where $Z$ is the number of molecules per unit cell, $M$ is molar mass, $N_A$ is Avogadro's number, and $V_{\text{cell}}$ is the unit cell volume in cm³. Calculate the volume from the lattice parameters, then rearrange to solve for $Z$—this tells you the stoichiometry of the crystal structure.

The key is connecting density, molar mass, and unit cell volume to find how many formula units fit inside. Use the density formula $\rho = \frac{Z \times M}{N_A \times V_{\text{cell}}}$, where $Z$ is the number of molecules per unit cell, $M$ is molar mass, $N_A$ is Avogadro's number, and $V_{\text{cell}}$ is the unit cell volume in cm³. Calculate the volume from the lattice parameters, then rearrange to solve for $Z$—this tells you the stoichiometry of the crystal structure.