Work out unit cell density instantly with clear inputs, formula shown and shareable results.
A crystal's density is the mass inside one unit cell divided by the cell's volume. The mass is the atoms per cell times the molar mass over the Avogadro constant; the volume is the cube of the edge. Copper with four atoms per face-centred cell, 63.55 g/mol and a 361.5 pm edge comes out at 8.93 g/cm3, matching the measured value.
Cell mass
mass = Z x M / NA
Density
rho = Z x M / (NA x a^3)
Because the edge length comes from diffraction. Comparing it to the measured bulk density reveals porosity or vacancies.
One for simple cubic, two for body-centred cubic, four for face-centred cubic, and eight for the diamond structure.