Chemical bond properties and hardness of Ca4REO(BO3)3 (RE = Sm, Gd)

The chemical bond parameters of Ca4GdO(BO3)3 and Ca4SmO(BO3)3 compounds have been calculated using the chemical bond theory of complex crystals. Their hardness has been predicted by the chemical bond definition of hardness. The calculated results indicate that their hardness is determined only by Ca–O, Gd–O bond. And the BO3 anionic cluster does not contribute to their hardness. The calculation of hardness indicates that all of the compounds possess good mechanical properties. The other properties of Ca4SmO(BO3)3 compounds have been calculated using first principles technique.