Vickers hardness (H V ) and bulk moduli (B 0 ) of new phases have been evaluated using the thermodynamic model based on thermodynamic properties and crystal structure. As it was shown earlier this model is the most reliable among all contemporary theoretical models of hardness, at least in the case of compounds of light elements. The fracture toughness (K Ic ) was estimated using Mazhnik-Oganov model , the only model that allows such predictions. Hardness and other mechanical properties are presented in Table .