The last columns of Table provides the obtained B V and G V . C 8 has the largest values, close to the accepted values for diamond B V =445 GPa and G V = 550 GPa . The three BN polytypes have close values with lower magnitudes than C 8 highlighting their similarities of structures differing by increasingly large extension. The ternaries show bulk and shear moduli closer to C 8 whence their labeling as hetero diamonds. Such trends are expected to reflect the hardness properties.