Monoclinic mixed crystals of halogenomethanes CBr4−nCln (n = 0, … , 4)

On the basis of the isostructural relationship between the low-temperature monoclinic (C2/c, Z = 32) phases of the halogenomethane CBr4−nCln (n = 0, … , 4), a set of mixed crystals has been analysed by means of high-resolution X-ray powder diffraction. It is shown that the monoclinic structure of pure and mixed crystals does not depend of the particularities of the dipolar (or dipole induced) interactions of the pure compound, neither on the composition of the mixed crystal, but on the relative content of the halogen atoms which controls the size of the molecule or the average molecule for the case of mixed crystals.