On the perfection of cleavage planes of potassium bichromate single crystals

The relative perfection of the 001, 100 and 100 cleavage planes of potassium bichromate single crystals is analysed by calculations of the surface energy of main crystallographic planes. The surface energy was determined for the three cleavage planes as well as for planes corresponding to other theoretically possible orientations. It was found that: (1) among different planes the calculated values of the surface energy of the 001, 100 and 010 cleavage planes of potassium bichromate are the lowest, (2) among the three cleavage planes the 001 perfect cleavage plane has the lowest surface energy, (3) the relative perfection of different cleavage planes can be explained by using the coefficient δ proportional to the ratio of the surface energy of the hkl cleavage plane to the energy of dislocations emerging on the plane, and (4) the lower the values of the coefficient δ for a cleavage plane, the better is the cleavage perfection.