The mechanical stability criteria were obtained from the calculations of the elastic constants. The treatment of the results was done using the ELATE online tool , dedicated to the analysis of the elastic tensors. The program provides the bulk (B), shear (G) and Young's (E) moduli along different averaging methods; here the Voigt method was used. Two empirical models, Mazhnik-Oganov and Chen-Niu , have been used to estimate Vickers hardness (H V ) from elastic constants.