The elastic constants were calculated by performing finite distortions of the lattice around equilibrium positions. The calculated sets of elastic constants C ij (i and j correspond to directions) are given in Table . All C ij values are positive. The elastic constants of C 8 have the largest magnitudes, close to diamond . Structurally related new BN polytypes as well as wBN show the trend of decreasing C ij magnitudes. Then the mechanical properties were determined from the bulk (B) and the shear (G) moduli obtained by an averaging of the elastic constants. Herein, we used Voigt's method based on a uniform strain (cf. for original and modern publications). The four compounds can be differentiated from the bulk B V and shear G V moduli, obtained from the equations corresponding to the hexagonal system :