The density of totally crystalline polypropylene at room temperature is 0.946 g/cm3. Also, at room temperature the unit cell for this material is monoclinic with lattice parameters
a = 0.666 nm α = 90°
b = 2.078 nm β = 99.62°
c = 0.650 nm γ = 90°
If the volume of a monoclinic unit cell, Vmono, is a function of these lattice parameters as
Vmono = abc sin β
determine the number of repeat units per unit cell.