Density value P calculated from the crystal cell and contents, expressed as per cent solvent. P = 1 - (1.23 N MMass) / V N = the number of molecules in the unit cell MMass = the molecular mass of each molecule (gm/mole) V = the volume of the unit cell (A^3^) 1.23 = a conversion factor evaluated as: (0.74 cm^3^/g) (10^24^ A^3^/cm^3^) -------------------------------------- (6.02*10^23^) molecules/mole where 0.74 is an assumed value for the partial specific volume of the molecule